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<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* This class represent the base generator class where all the needed functions to generate proper SQL are defined.
*
* The rest of classes will inherit, by default, the same logic.
* Functions will be overridden as needed to generate correct SQL.
*
* @package core_ddl
* @copyright 1999 onwards Martin Dougiamas http://dougiamas.com
* 2001-3001 Eloy Lafuente (stronk7) http://contiento.com
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
defined('MOODLE_INTERNAL') || die();
/**
* Abstract sql generator class, base for all db specific implementations.
*
* @package core_ddl
* @copyright 1999 onwards Martin Dougiamas http://dougiamas.com
* 2001-3001 Eloy Lafuente (stronk7) http://contiento.com
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
abstract class sql_generator {
// Please, avoid editing this defaults in this base class!
// It could change the behaviour of the rest of generators
// that, by default, inherit this configuration.
// To change any of them, do it in extended classes instead.
/** @var string Used to quote names. */
public $quote_string = '"';
/** @var string To be automatically added at the end of each statement. */
public $statement_end = ';';
/** @var bool To decide if we want to quote all the names or only the reserved ones. */
public $quote_all = false;
/** @var bool To create all the integers as NUMBER(x) (also called DECIMAL, NUMERIC...). */
public $integer_to_number = false;
/** @var bool To create all the floats as NUMBER(x) (also called DECIMAL, NUMERIC...). */
public $float_to_number = false;
/** @var string Proper type for NUMBER(x) in this DB. */
public $number_type = 'NUMERIC';
/** @var string To define the default to set for NOT NULLs CHARs without default (null=do nothing).*/
public $default_for_char = null;
/** @var bool To specify if the generator must use some DEFAULT clause to drop defaults.*/
public $drop_default_value_required = false;
/** @var string The DEFAULT clause required to drop defaults.*/
public $drop_default_value = '';
/** @var bool To decide if the default clause of each field must go after the null clause.*/
public $default_after_null = true;
/** @var bool To force the generator if NULL clauses must be specified. It shouldn't be necessary.*/
public $specify_nulls = false;
/** @var string To force primary key names to one string (null=no force).*/
public $primary_key_name = null;
/** @var bool True if the generator builds primary keys.*/
public $primary_keys = true;
/** @var bool True if the generator builds unique keys.*/
public $unique_keys = false;
/** @var bool True if the generator builds foreign keys.*/
public $foreign_keys = false;
/** @var string Template to drop PKs. 'TABLENAME' and 'KEYNAME' will be replaced from this template.*/
public $drop_primary_key = 'ALTER TABLE TABLENAME DROP CONSTRAINT KEYNAME';
/** @var string Template to drop UKs. 'TABLENAME' and 'KEYNAME' will be replaced from this template.*/
public $drop_unique_key = 'ALTER TABLE TABLENAME DROP CONSTRAINT KEYNAME';
/** @var string Template to drop FKs. 'TABLENAME' and 'KEYNAME' will be replaced from this template.*/
public $drop_foreign_key = 'ALTER TABLE TABLENAME DROP CONSTRAINT KEYNAME';
/** @var bool True if the generator needs to add extra code to generate the sequence fields.*/
public $sequence_extra_code = true;
/** @var string The particular name for inline sequences in this generator.*/
public $sequence_name = 'auto_increment';
/** @var string|bool Different name for small (4byte) sequences or false if same.*/
public $sequence_name_small = false;
/**
* @var bool To avoid outputting the rest of the field specs, leaving only the name and the sequence_name returned.
* @see getFieldSQL()
*/
public $sequence_only = false;
/** @var bool True if the generator needs to add code for table comments.*/
public $add_table_comments = true;
/** @var bool True if the generator needs to add the after clause for fields.*/
public $add_after_clause = false;
/**
* @var bool True if the generator needs to prepend the prefix to all the key/index/sequence/trigger/check names.
* @see $prefix
*/
public $prefix_on_names = true;
/** @var int Maximum length for key/index/sequence/trigger/check names (keep 30 for all!).*/
public $names_max_length = 30;
/** @var string Characters to be used as concatenation operator. If not defined, MySQL CONCAT function will be used.*/
public $concat_character = '||';
/** @var string SQL sentence to rename one table, both 'OLDNAME' and 'NEWNAME' keywords are dynamically replaced.*/
public $rename_table_sql = 'ALTER TABLE OLDNAME RENAME TO NEWNAME';
/** @var string SQL sentence to drop one table where the 'TABLENAME' keyword is dynamically replaced.*/
public $drop_table_sql = 'DROP TABLE TABLENAME';
/** @var string The SQL template to alter columns where the 'TABLENAME' and 'COLUMNSPECS' keywords are dynamically replaced.*/
public $alter_column_sql = 'ALTER TABLE TABLENAME ALTER COLUMN COLUMNSPECS';
/** @var bool The generator will skip the default clause on alter columns.*/
public $alter_column_skip_default = false;
/** @var bool The generator will skip the type clause on alter columns.*/
public $alter_column_skip_type = false;
/** @var bool The generator will skip the null/notnull clause on alter columns.*/
public $alter_column_skip_notnull = false;
/** @var string SQL sentence to rename one column where 'TABLENAME', 'OLDFIELDNAME' and 'NEWFIELDNAME' keywords are dynamically replaced.*/
public $rename_column_sql = 'ALTER TABLE TABLENAME RENAME COLUMN OLDFIELDNAME TO NEWFIELDNAME';
/** @var string SQL sentence to drop one index where 'TABLENAME', 'INDEXNAME' keywords are dynamically replaced.*/
public $drop_index_sql = 'DROP INDEX INDEXNAME';
/** @var string SQL sentence to rename one index where 'TABLENAME', 'OLDINDEXNAME' and 'NEWINDEXNAME' are dynamically replaced.*/
public $rename_index_sql = 'ALTER INDEX OLDINDEXNAME RENAME TO NEWINDEXNAME';
/** @var string SQL sentence to rename one key 'TABLENAME', 'OLDKEYNAME' and 'NEWKEYNAME' are dynamically replaced.*/
public $rename_key_sql = 'ALTER TABLE TABLENAME CONSTRAINT OLDKEYNAME RENAME TO NEWKEYNAME';
/** @var string The prefix to be used for all the DB objects.*/
public $prefix;
/** @var string List of reserved words (in order to quote them properly).*/
public $reserved_words;
/** @var moodle_database The moodle_database instance.*/
public $mdb;
/** @var Control existing temptables.*/
protected $temptables;
/**
* Creates a new sql_generator.
* @param moodle_database $mdb The moodle_database object instance.
* @param moodle_temptables $temptables The optional moodle_temptables instance, null by default.
*/
public function __construct($mdb, $temptables = null) {
$this->prefix = $mdb->get_prefix();
$this->reserved_words = $this->getReservedWords();
$this->mdb = $mdb; // this creates circular reference - the other link must be unset when closing db
$this->temptables = $temptables;
}
/**
* Releases all resources.
*/
public function dispose() {
$this->mdb = null;
}
/**
* Given one string (or one array), ends it with $statement_end .
*
* @see $statement_end
*
* @param array|string $input SQL statement(s).
* @return array|string
*/
public function getEndedStatements($input) {
if (is_array($input)) {
foreach ($input as $key=>$content) {
$input[$key] = $this->getEndedStatements($content);
}
return $input;
} else {
$input = trim($input).$this->statement_end;
return $input;
}
}
/**
* Given one xmldb_table, checks if it exists in DB (true/false).
*
* @param mixed $table The table to be searched (string name or xmldb_table instance).
* @return boolean true/false
*/
public function table_exists($table) {
if (is_string($table)) {
$tablename = $table;
} else {
// Calculate the name of the table
$tablename = $table->getName();
}
if ($this->temptables->is_temptable($tablename)) {
return true;
}
// Get all tables in moodle database.
$tables = $this->mdb->get_tables();
return isset($tables[$tablename]);
}
/**
* This function will return the SQL code needed to create db tables and statements.
* @see xmldb_structure
*
* @param xmldb_structure $xmldb_structure An xmldb_structure instance.
* @return array
*/
public function getCreateStructureSQL($xmldb_structure) {
$results = array();
if ($tables = $xmldb_structure->getTables()) {
foreach ($tables as $table) {
$results = array_merge($results, $this->getCreateTableSQL($table));
}
}
return $results;
}
/**
* Given one xmldb_table, this returns it's correct name, depending of all the parameterization.
* eg: This appends $prefix to the table name.
*
* @see $prefix
*
* @param xmldb_table $xmldb_table The table whose name we want.
* @param boolean $quoted To specify if the name must be quoted (if reserved word, only!).
* @return string The correct name of the table.
*/
public function getTableName(xmldb_table $xmldb_table, $quoted=true) {
// Get the name
$tablename = $this->prefix.$xmldb_table->getName();
// Apply quotes optionally
if ($quoted) {
$tablename = $this->getEncQuoted($tablename);
}
return $tablename;
}
/**
* Given one correct xmldb_table, returns the SQL statements
* to create it (inside one array).
*
* @param xmldb_table $xmldb_table An xmldb_table instance.
* @return array An array of SQL statements, starting with the table creation SQL followed
* by any of its comments, indexes and sequence creation SQL statements.
*/
public function getCreateTableSQL($xmldb_table) {
if ($error = $xmldb_table->validateDefinition()) {
throw new coding_exception($error);
}
$results = array(); //Array where all the sentences will be stored
// Table header
$table = 'CREATE TABLE ' . $this->getTableName($xmldb_table) . ' (';
if (!$xmldb_fields = $xmldb_table->getFields()) {
return $results;
}
$sequencefield = null;
// Add the fields, separated by commas
foreach ($xmldb_fields as $xmldb_field) {
if ($xmldb_field->getSequence()) {
$sequencefield = $xmldb_field->getName();
}
$table .= "\n " . $this->getFieldSQL($xmldb_table, $xmldb_field);
$table .= ',';
}
// Add the keys, separated by commas
if ($xmldb_keys = $xmldb_table->getKeys()) {
foreach ($xmldb_keys as $xmldb_key) {
if ($keytext = $this->getKeySQL($xmldb_table, $xmldb_key)) {
$table .= "\nCONSTRAINT " . $keytext . ',';
}
// If the key is XMLDB_KEY_FOREIGN_UNIQUE, create it as UNIQUE too
if ($xmldb_key->getType() == XMLDB_KEY_FOREIGN_UNIQUE) {
//Duplicate the key
$xmldb_key->setType(XMLDB_KEY_UNIQUE);
if ($keytext = $this->getKeySQL($xmldb_table, $xmldb_key)) {
$table .= "\nCONSTRAINT " . $keytext . ',';
}
}
// make sure sequence field is unique
if ($sequencefield and $xmldb_key->getType() == XMLDB_KEY_PRIMARY) {
$fields = $xmldb_key->getFields();
$field = reset($fields);
if ($sequencefield === $field) {
$sequencefield = null;
}
}
}
}
// throw error if sequence field does not have unique key defined
if ($sequencefield) {
throw new ddl_exception('ddsequenceerror', $xmldb_table->getName());
}
// Table footer, trim the latest comma
$table = trim($table,',');
$table .= "\n)";
// Add the CREATE TABLE to results
$results[] = $table;
// Add comments if specified and it exists
if ($this->add_table_comments && $xmldb_table->getComment()) {
$comment = $this->getCommentSQL($xmldb_table);
// Add the COMMENT to results
$results = array_merge($results, $comment);
}
// Add the indexes (each one, one statement)
if ($xmldb_indexes = $xmldb_table->getIndexes()) {
foreach ($xmldb_indexes as $xmldb_index) {
//tables do not exist yet, which means indexed can not exist yet
if ($indextext = $this->getCreateIndexSQL($xmldb_table, $xmldb_index)) {
$results = array_merge($results, $indextext);
}
}
}
// Also, add the indexes needed from keys, based on configuration (each one, one statement)
if ($xmldb_keys = $xmldb_table->getKeys()) {
foreach ($xmldb_keys as $xmldb_key) {
// If we aren't creating the keys OR if the key is XMLDB_KEY_FOREIGN (not underlying index generated
// automatically by the RDBMS) create the underlying (created by us) index (if doesn't exists)
if (!$this->getKeySQL($xmldb_table, $xmldb_key) || $xmldb_key->getType() == XMLDB_KEY_FOREIGN) {
// Create the interim index
$index = new xmldb_index('anyname');
$index->setFields($xmldb_key->getFields());
//tables do not exist yet, which means indexed can not exist yet
$createindex = false; //By default
switch ($xmldb_key->getType()) {
case XMLDB_KEY_UNIQUE:
case XMLDB_KEY_FOREIGN_UNIQUE:
$index->setUnique(true);
$createindex = true;
break;
case XMLDB_KEY_FOREIGN:
$index->setUnique(false);
$createindex = true;
break;
}
if ($createindex) {
if ($indextext = $this->getCreateIndexSQL($xmldb_table, $index)) {
// Add the INDEX to the array
$results = array_merge($results, $indextext);
}
}
}
}
}
// Add sequence extra code if needed
if ($this->sequence_extra_code) {
// Iterate over fields looking for sequences
foreach ($xmldb_fields as $xmldb_field) {
if ($xmldb_field->getSequence()) {
// returns an array of statements needed to create one sequence
$sequence_sentences = $this->getCreateSequenceSQL($xmldb_table, $xmldb_field);
// Add the SEQUENCE to the array
$results = array_merge($results, $sequence_sentences);
}
}
}
return $results;
}
/**
* Given one correct xmldb_index, returns the SQL statements
* needed to create it (in array).
*
* @param xmldb_table $xmldb_table The xmldb_table instance to create the index on.
* @param xmldb_index $xmldb_index The xmldb_index to create.
* @return array An array of SQL statements to create the index.
* @throws coding_exception Thrown if the xmldb_index does not validate with the xmldb_table.
*/
public function getCreateIndexSQL($xmldb_table, $xmldb_index) {
if ($error = $xmldb_index->validateDefinition($xmldb_table)) {
throw new coding_exception($error);
}
$unique = '';
$suffix = 'ix';
if ($xmldb_index->getUnique()) {
$unique = ' UNIQUE';
$suffix = 'uix';
}
$index = 'CREATE' . $unique . ' INDEX ';
$index .= $this->getNameForObject($xmldb_table->getName(), implode(', ', $xmldb_index->getFields()), $suffix);
$index .= ' ON ' . $this->getTableName($xmldb_table);
$index .= ' (' . implode(', ', $this->getEncQuoted($xmldb_index->getFields())) . ')';
return array($index);
}
/**
* Given one correct xmldb_field, returns the complete SQL line to create it.
*
* @param xmldb_table $xmldb_table The table related to $xmldb_field.
* @param xmldb_field $xmldb_field The instance of xmldb_field to create the SQL from.
* @param string $skip_type_clause The type clause on alter columns, NULL by default.
* @param string $skip_default_clause The default clause on alter columns, NULL by default.
* @param string $skip_notnull_clause The null/notnull clause on alter columns, NULL by default.
* @param string $specify_nulls_clause To force a specific null clause, NULL by default.
* @param bool $specify_field_name Flag to specify fieldname in return.
* @return string The field generating SQL statement.
* @throws coding_exception Thrown when xmldb_field doesn't validate with the xmldb_table.
*/
public function getFieldSQL($xmldb_table, $xmldb_field, $skip_type_clause = NULL, $skip_default_clause = NULL, $skip_notnull_clause = NULL, $specify_nulls_clause = NULL, $specify_field_name = true) {
if ($error = $xmldb_field->validateDefinition($xmldb_table)) {
throw new coding_exception($error);
}
$skip_type_clause = is_null($skip_type_clause) ? $this->alter_column_skip_type : $skip_type_clause;
$skip_default_clause = is_null($skip_default_clause) ? $this->alter_column_skip_default : $skip_default_clause;
$skip_notnull_clause = is_null($skip_notnull_clause) ? $this->alter_column_skip_notnull : $skip_notnull_clause;
$specify_nulls_clause = is_null($specify_nulls_clause) ? $this->specify_nulls : $specify_nulls_clause;
// First of all, convert integers to numbers if defined
if ($this->integer_to_number) {
if ($xmldb_field->getType() == XMLDB_TYPE_INTEGER) {
$xmldb_field->setType(XMLDB_TYPE_NUMBER);
}
}
// Same for floats
if ($this->float_to_number) {
if ($xmldb_field->getType() == XMLDB_TYPE_FLOAT) {
$xmldb_field->setType(XMLDB_TYPE_NUMBER);
}
}
$field = ''; // Let's accumulate the whole expression based on params and settings
// The name
if ($specify_field_name) {
$field .= $this->getEncQuoted($xmldb_field->getName());
}
// The type and length only if we don't want to skip it
if (!$skip_type_clause) {
// The type and length
$field .= ' ' . $this->getTypeSQL($xmldb_field->getType(), $xmldb_field->getLength(), $xmldb_field->getDecimals());
}
// note: unsigned is not supported any more since moodle 2.3, all numbers are signed
// Calculate the not null clause
$notnull = '';
// Only if we don't want to skip it
if (!$skip_notnull_clause) {
if ($xmldb_field->getNotNull()) {
$notnull = ' NOT NULL';
} else {
if ($specify_nulls_clause) {
$notnull = ' NULL';
}
}
}
// Calculate the default clause
$default_clause = '';
if (!$skip_default_clause) { //Only if we don't want to skip it
$default_clause = $this->getDefaultClause($xmldb_field);
}
// Based on default_after_null, set both clauses properly
if ($this->default_after_null) {
$field .= $notnull . $default_clause;
} else {
$field .= $default_clause . $notnull;
}
// The sequence
if ($xmldb_field->getSequence()) {
if($xmldb_field->getLength()<=9 && $this->sequence_name_small) {
$sequencename=$this->sequence_name_small;
} else {
$sequencename=$this->sequence_name;
}
$field .= ' ' . $sequencename;
if ($this->sequence_only) {
// We only want the field name and sequence name to be printed
// so, calculate it and return
$sql = $this->getEncQuoted($xmldb_field->getName()) . ' ' . $sequencename;
return $sql;
}
}
return $field;
}
/**
* Given one correct xmldb_key, returns its specs.
*
* @param xmldb_table $xmldb_table The table related to $xmldb_key.
* @param xmldb_key $xmldb_key The xmldb_key's specifications requested.
* @return string SQL statement about the xmldb_key.
*/
public function getKeySQL($xmldb_table, $xmldb_key) {
$key = '';
switch ($xmldb_key->getType()) {
case XMLDB_KEY_PRIMARY:
if ($this->primary_keys) {
if ($this->primary_key_name !== null) {
$key = $this->getEncQuoted($this->primary_key_name);
} else {
$key = $this->getNameForObject($xmldb_table->getName(), implode(', ', $xmldb_key->getFields()), 'pk');
}
$key .= ' PRIMARY KEY (' . implode(', ', $this->getEncQuoted($xmldb_key->getFields())) . ')';
}
break;
case XMLDB_KEY_UNIQUE:
if ($this->unique_keys) {
$key = $this->getNameForObject($xmldb_table->getName(), implode(', ', $xmldb_key->getFields()), 'uk');
$key .= ' UNIQUE (' . implode(', ', $this->getEncQuoted($xmldb_key->getFields())) . ')';
}
break;
case XMLDB_KEY_FOREIGN:
case XMLDB_KEY_FOREIGN_UNIQUE:
if ($this->foreign_keys) {
$key = $this->getNameForObject($xmldb_table->getName(), implode(', ', $xmldb_key->getFields()), 'fk');
$key .= ' FOREIGN KEY (' . implode(', ', $this->getEncQuoted($xmldb_key->getFields())) . ')';
$key .= ' REFERENCES ' . $this->getEncQuoted($this->prefix . $xmldb_key->getRefTable());
$key .= ' (' . implode(', ', $this->getEncQuoted($xmldb_key->getRefFields())) . ')';
}
break;
}
return $key;
}
/**
* Give one xmldb_field, returns the correct "default value" for the current configuration
*
* @param xmldb_field $xmldb_field The field.
* @return The default value of the field.
*/
public function getDefaultValue($xmldb_field) {
$default = null;
if ($xmldb_field->getDefault() !== NULL) {
if ($xmldb_field->getType() == XMLDB_TYPE_CHAR ||
$xmldb_field->getType() == XMLDB_TYPE_TEXT) {
if ($xmldb_field->getDefault() === '') { // If passing empty default, use the $default_for_char one instead
$default = "'" . $this->default_for_char . "'";
} else {
$default = "'" . $this->addslashes($xmldb_field->getDefault()) . "'";
}
} else {
$default = $xmldb_field->getDefault();
}
} else {
// We force default '' for not null char columns without proper default
// some day this should be out!
if ($this->default_for_char !== NULL &&
$xmldb_field->getType() == XMLDB_TYPE_CHAR &&
$xmldb_field->getNotNull()) {
$default = "'" . $this->default_for_char . "'";
} else {
// If the DB requires to explicity define some clause to drop one default, do it here
// never applying defaults to TEXT and BINARY fields
if ($this->drop_default_value_required &&
$xmldb_field->getType() != XMLDB_TYPE_TEXT &&
$xmldb_field->getType() != XMLDB_TYPE_BINARY && !$xmldb_field->getNotNull()) {
$default = $this->drop_default_value;
}
}
}
return $default;
}
/**
* Given one xmldb_field, returns the correct "default clause" for the current configuration.
*
* @param xmldb_field $xmldb_field The xmldb_field.
* @return The SQL clause for generating the default value as in $xmldb_field.
*/
public function getDefaultClause($xmldb_field) {
$defaultvalue = $this->getDefaultValue ($xmldb_field);
if ($defaultvalue !== null) {
return ' DEFAULT ' . $defaultvalue;
} else {
return null;
}
}
/**
* Given one correct xmldb_table and the new name, returns the SQL statements
* to rename it (inside one array).
*
* @param xmldb_table $xmldb_table The table to rename.
* @param string $newname The new name to rename the table to.
* @return array SQL statement(s) to rename the table.
*/
public function getRenameTableSQL($xmldb_table, $newname) {
$results = array(); //Array where all the sentences will be stored
$newt = new xmldb_table($newname); //Temporal table for name calculations
$rename = str_replace('OLDNAME', $this->getTableName($xmldb_table), $this->rename_table_sql);
$rename = str_replace('NEWNAME', $this->getTableName($newt), $rename);
$results[] = $rename;
// Call to getRenameTableExtraSQL() override if needed
$extra_sentences = $this->getRenameTableExtraSQL($xmldb_table, $newname);
$results = array_merge($results, $extra_sentences);
return $results;
}
/**
* Given one correct xmldb_table, returns the SQL statements
* to drop it (inside one array). Works also for temporary tables.
*
* @param xmldb_table $xmldb_table The table to drop.
* @return array SQL statement(s) for dropping the specified table.
*/
public function getDropTableSQL($xmldb_table) {
$results = array(); //Array where all the sentences will be stored
$drop = str_replace('TABLENAME', $this->getTableName($xmldb_table), $this->drop_table_sql);
$results[] = $drop;
// call to getDropTableExtraSQL(), override if needed
$extra_sentences = $this->getDropTableExtraSQL($xmldb_table);
$results = array_merge($results, $extra_sentences);
return $results;
}
/**
* Performs any clean up that needs to be done after a table is dropped.
*
* @param xmldb_table $table
*/
public function cleanup_after_drop(xmldb_table $table): void {
if ($this->temptables->is_temptable($table->getName())) {
$this->temptables->delete_temptable($table->getName());
}
}
/**
* Given one xmldb_table and one xmldb_field, return the SQL statements needed to add the field to the table.
*
* @param xmldb_table $xmldb_table The table related to $xmldb_field.
* @param xmldb_field $xmldb_field The instance of xmldb_field to create the SQL from.
* @param string $skip_type_clause The type clause on alter columns, NULL by default.
* @param string $skip_default_clause The default clause on alter columns, NULL by default.
* @param string $skip_notnull_clause The null/notnull clause on alter columns, NULL by default.
* @return array The SQL statement for adding a field to the table.
*/
public function getAddFieldSQL($xmldb_table, $xmldb_field, $skip_type_clause = NULL, $skip_default_clause = NULL, $skip_notnull_clause = NULL) {
$skip_type_clause = is_null($skip_type_clause) ? $this->alter_column_skip_type : $skip_type_clause;
$skip_default_clause = is_null($skip_default_clause) ? $this->alter_column_skip_default : $skip_default_clause;
$skip_notnull_clause = is_null($skip_notnull_clause) ? $this->alter_column_skip_notnull : $skip_notnull_clause;
$results = array();
// Get the quoted name of the table and field
$tablename = $this->getTableName($xmldb_table);
// Build the standard alter table add
$sql = $this->getFieldSQL($xmldb_table, $xmldb_field, $skip_type_clause,
$skip_default_clause,
$skip_notnull_clause);
$altertable = 'ALTER TABLE ' . $tablename . ' ADD ' . $sql;
// Add the after clause if necessary
if ($this->add_after_clause && $xmldb_field->getPrevious()) {
$altertable .= ' AFTER ' . $this->getEncQuoted($xmldb_field->getPrevious());
}
$results[] = $altertable;
return $results;
}
/**
* Given one xmldb_table and one xmldb_field, return the SQL statements needed to drop the field from the table.
*
* @param xmldb_table $xmldb_table The table related to $xmldb_field.
* @param xmldb_field $xmldb_field The instance of xmldb_field to create the SQL from.
* @return array The SQL statement for dropping a field from the table.
*/
public function getDropFieldSQL($xmldb_table, $xmldb_field) {
$results = array();
// Get the quoted name of the table and field
$tablename = $this->getTableName($xmldb_table);
$fieldname = $this->getEncQuoted($xmldb_field->getName());
// Build the standard alter table drop
$results[] = 'ALTER TABLE ' . $tablename . ' DROP COLUMN ' . $fieldname;
return $results;
}
/**
* Given one xmldb_table and one xmldb_field, return the SQL statements needed to alter the field in the table.
*
* @param xmldb_table $xmldb_table The table related to $xmldb_field.
* @param xmldb_field $xmldb_field The instance of xmldb_field to create the SQL from.
* @param string $skip_type_clause The type clause on alter columns, NULL by default.
* @param string $skip_default_clause The default clause on alter columns, NULL by default.
* @param string $skip_notnull_clause The null/notnull clause on alter columns, NULL by default.
* @return string The field altering SQL statement.
*/
public function getAlterFieldSQL($xmldb_table, $xmldb_field, $skip_type_clause = NULL, $skip_default_clause = NULL, $skip_notnull_clause = NULL) {
$skip_type_clause = is_null($skip_type_clause) ? $this->alter_column_skip_type : $skip_type_clause;
$skip_default_clause = is_null($skip_default_clause) ? $this->alter_column_skip_default : $skip_default_clause;
$skip_notnull_clause = is_null($skip_notnull_clause) ? $this->alter_column_skip_notnull : $skip_notnull_clause;
$results = array();
// Get the quoted name of the table and field
$tablename = $this->getTableName($xmldb_table);
$fieldname = $this->getEncQuoted($xmldb_field->getName());
// Build de alter sentence using the alter_column_sql template
$alter = str_replace('TABLENAME', $this->getTableName($xmldb_table), $this->alter_column_sql);
$colspec = $this->getFieldSQL($xmldb_table, $xmldb_field, $skip_type_clause,
$skip_default_clause,
$skip_notnull_clause,
true);
$alter = str_replace('COLUMNSPECS', $colspec, $alter);
// Add the after clause if necessary
if ($this->add_after_clause && $xmldb_field->getPrevious()) {
$alter .= ' after ' . $this->getEncQuoted($xmldb_field->getPrevious());
}
// Build the standard alter table modify
$results[] = $alter;
return $results;
}
/**
* Given one xmldb_table and one xmldb_field, return the SQL statements needed to modify the default of the field in the table.
*
* @param xmldb_table $xmldb_table The table related to $xmldb_field.
* @param xmldb_field $xmldb_field The instance of xmldb_field to get the modified default value from.
* @return array The SQL statement for modifying the default value.
*/
public function getModifyDefaultSQL($xmldb_table, $xmldb_field) {
$results = array();
// Get the quoted name of the table and field
$tablename = $this->getTableName($xmldb_table);
$fieldname = $this->getEncQuoted($xmldb_field->getName());
// Decide if we are going to create/modify or to drop the default
if ($xmldb_field->getDefault() === null) {
$results = $this->getDropDefaultSQL($xmldb_table, $xmldb_field); //Drop
} else {
$results = $this->getCreateDefaultSQL($xmldb_table, $xmldb_field); //Create/modify
}
return $results;
}
/**
* Given one correct xmldb_field and the new name, returns the SQL statements
* to rename it (inside one array).
*
* @param xmldb_table $xmldb_table The table related to $xmldb_field.
* @param xmldb_field $xmldb_field The instance of xmldb_field to get the renamed field from.
* @param string $newname The new name to rename the field to.
* @return array The SQL statements for renaming the field.
*/
public function getRenameFieldSQL($xmldb_table, $xmldb_field, $newname) {
$results = array(); //Array where all the sentences will be stored
// Although this is checked in database_manager::rename_field() - double check
// that we aren't trying to rename one "id" field. Although it could be
// implemented (if adding the necessary code to rename sequences, defaults,
// triggers... and so on under each getRenameFieldExtraSQL() function, it's
// better to forbid it, mainly because this field is the default PK and
// in the future, a lot of FKs can be pointing here. So, this field, more
// or less, must be considered immutable!
if ($xmldb_field->getName() == 'id') {
return array();
}
$rename = str_replace('TABLENAME', $this->getTableName($xmldb_table), $this->rename_column_sql);
$rename = str_replace('OLDFIELDNAME', $this->getEncQuoted($xmldb_field->getName()), $rename);
$rename = str_replace('NEWFIELDNAME', $this->getEncQuoted($newname), $rename);
$results[] = $rename;
// Call to getRenameFieldExtraSQL(), override if needed
$extra_sentences = $this->getRenameFieldExtraSQL($xmldb_table, $xmldb_field, $newname);
$results = array_merge($results, $extra_sentences);
return $results;
}
/**
* Given one xmldb_table and one xmldb_key, return the SQL statements needed to add the key to the table
* note that undelying indexes will be added as parametrised by $xxxx_keys and $xxxx_index parameters.
*
* @param xmldb_table $xmldb_table The table related to $xmldb_key.
* @param xmldb_key $xmldb_key The xmldb_key to add.
* @return array SQL statement to add the xmldb_key.
*/
public function getAddKeySQL($xmldb_table, $xmldb_key) {
$results = array();
// Just use the CreateKeySQL function
if ($keyclause = $this->getKeySQL($xmldb_table, $xmldb_key)) {
$key = 'ALTER TABLE ' . $this->getTableName($xmldb_table) .
' ADD CONSTRAINT ' . $keyclause;
$results[] = $key;
}
// If we aren't creating the keys OR if the key is XMLDB_KEY_FOREIGN (not underlying index generated
// automatically by the RDBMS) create the underlying (created by us) index (if doesn't exists)
if (!$keyclause || $xmldb_key->getType() == XMLDB_KEY_FOREIGN) {
// Only if they don't exist
if ($xmldb_key->getType() == XMLDB_KEY_FOREIGN) { //Calculate type of index based on type ok key
$indextype = XMLDB_INDEX_NOTUNIQUE;
} else {
$indextype = XMLDB_INDEX_UNIQUE;
}
$xmldb_index = new xmldb_index('anyname', $indextype, $xmldb_key->getFields());
if (!$this->mdb->get_manager()->index_exists($xmldb_table, $xmldb_index)) {
$results = array_merge($results, $this->getAddIndexSQL($xmldb_table, $xmldb_index));
}
}
// If the key is XMLDB_KEY_FOREIGN_UNIQUE, create it as UNIQUE too
if ($xmldb_key->getType() == XMLDB_KEY_FOREIGN_UNIQUE && $this->unique_keys) {
//Duplicate the key
$xmldb_key->setType(XMLDB_KEY_UNIQUE);
$results = array_merge($results, $this->getAddKeySQL($xmldb_table, $xmldb_key));
}
// Return results
return $results;
}
/**
* Given one xmldb_table and one xmldb_index, return the SQL statements needed to drop the index from the table.
*
* @param xmldb_table $xmldb_table The table related to $xmldb_key.
* @param xmldb_key $xmldb_key The xmldb_key to drop.
* @return array SQL statement to drop the xmldb_key.
*/
public function getDropKeySQL($xmldb_table, $xmldb_key) {
$results = array();
// Get the key name (note that this doesn't introspect DB, so could cause some problems sometimes!)
// TODO: We'll need to overwrite the whole getDropKeySQL() method inside each DB to do the proper queries
// against the dictionary or require ADOdb to support it or change the find_key_name() method to
// perform DB introspection directly. But, for now, as we aren't going to enable referential integrity
// it won't be a problem at all
$dbkeyname = $this->mdb->get_manager()->find_key_name($xmldb_table, $xmldb_key);
// Only if such type of key generation is enabled
$dropkey = false;
switch ($xmldb_key->getType()) {
case XMLDB_KEY_PRIMARY:
if ($this->primary_keys) {
$template = $this->drop_primary_key;
$dropkey = true;
}
break;
case XMLDB_KEY_UNIQUE:
if ($this->unique_keys) {
$template = $this->drop_unique_key;
$dropkey = true;
}
break;
case XMLDB_KEY_FOREIGN_UNIQUE:
case XMLDB_KEY_FOREIGN:
if ($this->foreign_keys) {
$template = $this->drop_foreign_key;
$dropkey = true;
}
break;
}
// If we have decided to drop the key, let's do it
if ($dropkey) {
// Replace TABLENAME, CONSTRAINTTYPE and KEYNAME as needed
$dropsql = str_replace('TABLENAME', $this->getTableName($xmldb_table), $template);
$dropsql = str_replace('KEYNAME', $dbkeyname, $dropsql);
$results[] = $dropsql;
}
// If we aren't dropping the keys OR if the key is XMLDB_KEY_FOREIGN (not underlying index generated
// automatically by the RDBMS) drop the underlying (created by us) index (if exists)
if (!$dropkey || $xmldb_key->getType() == XMLDB_KEY_FOREIGN) {
// Only if they exist
$xmldb_index = new xmldb_index('anyname', XMLDB_INDEX_UNIQUE, $xmldb_key->getFields());
if ($this->mdb->get_manager()->index_exists($xmldb_table, $xmldb_index)) {
$results = array_merge($results, $this->getDropIndexSQL($xmldb_table, $xmldb_index));
}
}
// If the key is XMLDB_KEY_FOREIGN_UNIQUE, drop the UNIQUE too
if ($xmldb_key->getType() == XMLDB_KEY_FOREIGN_UNIQUE && $this->unique_keys) {
//Duplicate the key
$xmldb_key->setType(XMLDB_KEY_UNIQUE);
$results = array_merge($results, $this->getDropKeySQL($xmldb_table, $xmldb_key));
}
// Return results
return $results;
}
/**
* Given one xmldb_table and one xmldb_key, return the SQL statements needed to rename the key in the table
* Experimental! Shouldn't be used at all!
*
* @param xmldb_table $xmldb_table The table related to $xmldb_key.
* @param xmldb_key $xmldb_key The xmldb_key to rename.
* @param string $newname The xmldb_key's new name.
* @return array SQL statement to rename the xmldb_key.
*/
public function getRenameKeySQL($xmldb_table, $xmldb_key, $newname) {
$results = array();
// Get the real key name
$dbkeyname = $this->mdb->get_manager()->find_key_name($xmldb_table, $xmldb_key);
// Check we are really generating this type of keys
if (($xmldb_key->getType() == XMLDB_KEY_PRIMARY && !$this->primary_keys) ||
($xmldb_key->getType() == XMLDB_KEY_UNIQUE && !$this->unique_keys) ||
($xmldb_key->getType() == XMLDB_KEY_FOREIGN && !$this->foreign_keys) ||
($xmldb_key->getType() == XMLDB_KEY_FOREIGN_UNIQUE && !$this->unique_keys && !$this->foreign_keys)) {
// We aren't generating this type of keys, delegate to child indexes
$xmldb_index = new xmldb_index($xmldb_key->getName());
$xmldb_index->setFields($xmldb_key->getFields());
return $this->getRenameIndexSQL($xmldb_table, $xmldb_index, $newname);
}
// Arrived here so we are working with keys, lets rename them
// Replace TABLENAME and KEYNAME as needed
$renamesql = str_replace('TABLENAME', $this->getTableName($xmldb_table), $this->rename_key_sql);
$renamesql = str_replace('OLDKEYNAME', $dbkeyname, $renamesql);
$renamesql = str_replace('NEWKEYNAME', $newname, $renamesql);
// Some DB doesn't support key renaming so this can be empty
if ($renamesql) {
$results[] = $renamesql;
}
return $results;
}
/**
* Given one xmldb_table and one xmldb_index, return the SQL statements needed to add the index to the table.
*
* @param xmldb_table $xmldb_table The xmldb_table instance to add the index on.
* @param xmldb_index $xmldb_index The xmldb_index to add.
* @return array An array of SQL statements to add the index.
*/
public function getAddIndexSQL($xmldb_table, $xmldb_index) {
// Just use the CreateIndexSQL function
return $this->getCreateIndexSQL($xmldb_table, $xmldb_index);
}
/**
* Given one xmldb_table and one xmldb_index, return the SQL statements needed to drop the index from the table.
*
* @param xmldb_table $xmldb_table The xmldb_table instance to drop the index on.
* @param xmldb_index $xmldb_index The xmldb_index to drop.
* @return array An array of SQL statements to drop the index.
*/
public function getDropIndexSQL($xmldb_table, $xmldb_index) {
$results = array();
// Get the real index name
$dbindexnames = $this->mdb->get_manager()->find_index_name($xmldb_table, $xmldb_index, true);
// Replace TABLENAME and INDEXNAME as needed
if ($dbindexnames) {
foreach ($dbindexnames as $dbindexname) {
$dropsql = str_replace('TABLENAME', $this->getTableName($xmldb_table), $this->drop_index_sql);
$dropsql = str_replace('INDEXNAME', $this->getEncQuoted($dbindexname), $dropsql);
$results[] = $dropsql;
}
}
return $results;
}
/**
* Given one xmldb_table and one xmldb_index, return the SQL statements needed to rename the index in the table
* Experimental! Shouldn't be used at all!
*
* @param xmldb_table $xmldb_table The xmldb_table instance to rename the index on.
* @param xmldb_index $xmldb_index The xmldb_index to rename.
* @param string $newname The xmldb_index's new name.
* @return array An array of SQL statements to rename the index.
*/
function getRenameIndexSQL($xmldb_table, $xmldb_index, $newname) {
// Some DB doesn't support index renaming (MySQL) so this can be empty
if (empty($this->rename_index_sql)) {
return array();
}
// Get the real index name
$dbindexname = $this->mdb->get_manager()->find_index_name($xmldb_table, $xmldb_index);
// Replace TABLENAME and INDEXNAME as needed
$renamesql = str_replace('TABLENAME', $this->getTableName($xmldb_table), $this->rename_index_sql);
$renamesql = str_replace('OLDINDEXNAME', $this->getEncQuoted($dbindexname), $renamesql);
$renamesql = str_replace('NEWINDEXNAME', $this->getEncQuoted($newname), $renamesql);
return array($renamesql);
}
/**
* Given three strings (table name, list of fields (comma separated) and suffix),
* create the proper object name quoting it if necessary.
*
* IMPORTANT: This function must be used to CALCULATE NAMES of objects TO BE CREATED,
* NEVER TO GUESS NAMES of EXISTING objects!!!
*
* @param string $tablename The table name.
* @param string $fields A list of comma separated fields.
* @param string $suffix A suffix for the object name.
* @return string Object's name.
*/
public function getNameForObject($tablename, $fields, $suffix='') {
$name = '';
// Implement one basic cache to avoid object name duplication
// along all the request life, but never to return cached results
// We need this because sql statements are created before executing
// them, hence names doesn't exist "physically" yet in DB, so we need
// to known which ones have been used.
// We track all the keys used, and the previous counters to make subsequent creates faster.
// This may happen a lot with things like bulk backups or restores.
static $usednames = array();
static $previouscounters = array();
// Use standard naming. See http://docs.moodle.org/en/XMLDB_key_and_index_naming
$tablearr = explode ('_', $tablename);
foreach ($tablearr as $table) {
$name .= substr(trim($table),0,4);
}
$name .= '_';
$fieldsarr = explode (',', $fields);
foreach ($fieldsarr as $field) {
$name .= substr(trim($field),0,3);
}
// Prepend the prefix
$name = trim($this->prefix . $name);
// Make sure name does not exceed the maximum name length and add suffix.
$maxlengthwithoutsuffix = $this->names_max_length - strlen($suffix) - ($suffix ? 1 : 0);
$namewithsuffix = substr($name, 0, $maxlengthwithoutsuffix) . ($suffix ? ('_' . $suffix) : '');
if (isset($previouscounters[$name])) {
// If we have a counter stored, we will need to modify the key to the next counter location.
$counter = $previouscounters[$name] + 1;
$namewithsuffix = substr($name, 0, $maxlengthwithoutsuffix - strlen($counter)) .
$counter . ($suffix ? ('_' . $suffix) : '');
} else {
$counter = 1;
}
// If the calculated name is in the cache, or if we detect it by introspecting the DB let's modify it.
while (isset($usednames[$namewithsuffix]) || $this->isNameInUse($namewithsuffix, $suffix, $tablename)) {
// Now iterate until not used name is found, incrementing the counter
$counter++;
$namewithsuffix = substr($name, 0, $maxlengthwithoutsuffix - strlen($counter)) .
$counter . ($suffix ? ('_' . $suffix) : '');
}
// Add the name to the cache. Using key look with isset because it is much faster than in_array.
$usednames[$namewithsuffix] = true;
$previouscounters[$name] = $counter;
// Quote it if necessary (reserved words)
$namewithsuffix = $this->getEncQuoted($namewithsuffix);
return $namewithsuffix;
}
/**
* Given any string (or one array), enclose it by the proper quotes
* if it's a reserved word
*
* @param string|array $input String to quote.
* @return string|array Quoted string.
*/
public function getEncQuoted($input) {
if (is_array($input)) {
foreach ($input as $key=>$content) {
$input[$key] = $this->getEncQuoted($content);
}
return $input;
} else {
// Always lowercase
$input = strtolower($input);
// if reserved or quote_all or has hyphens, quote it
if ($this->quote_all || in_array($input, $this->reserved_words) || strpos($input, '-') !== false) {
$input = $this->quote_string . $input . $this->quote_string;
}
return $input;
}
}
/**
* Given one XMLDB Statement, build the needed SQL insert sentences to execute it.
*
* @param string $statement SQL statement.
* @return array Array of sentences in the SQL statement.
*/
function getExecuteInsertSQL($statement) {
$results = array(); //Array where all the sentences will be stored
if ($sentences = $statement->getSentences()) {
foreach ($sentences as $sentence) {
// Get the list of fields
$fields = $statement->getFieldsFromInsertSentence($sentence);
// Get the values of fields
$values = $statement->getValuesFromInsertSentence($sentence);
// Look if we have some CONCAT value and transform it dynamically
foreach($values as $key => $value) {
// Trim single quotes
$value = trim($value,"'");
if (stristr($value, 'CONCAT') !== false){
// Look for data between parenthesis
preg_match("/CONCAT\s*\((.*)\)$/is", trim($value), $matches);
if (isset($matches[1])) {
$part = $matches[1];
// Convert the comma separated string to an array
$arr = xmldb_object::comma2array($part);
if ($arr) {
$value = $this->getConcatSQL($arr);
}
}
}
// Values to be sent to DB must be properly escaped
$value = $this->addslashes($value);
// Back trimmed quotes
$value = "'" . $value . "'";
// Back to the array
$values[$key] = $value;
}
// Iterate over fields, escaping them if necessary
foreach($fields as $key => $field) {
$fields[$key] = $this->getEncQuoted($field);
}
// Build the final SQL sentence and add it to the array of results
$sql = 'INSERT INTO ' . $this->getEncQuoted($this->prefix . $statement->getTable()) .
'(' . implode(', ', $fields) . ') ' .
'VALUES (' . implode(', ', $values) . ')';
$results[] = $sql;
}
}
return $results;
}
/**
* Given one array of elements, build the proper CONCAT expression, based
* in the $concat_character setting. If such setting is empty, then
* MySQL's CONCAT function will be used instead.
*
* @param array $elements An array of elements to concatenate.
* @return mixed Returns the result of moodle_database::sql_concat() or false.
* @uses moodle_database::sql_concat()
* @uses call_user_func_array()
*/
public function getConcatSQL($elements) {
// Replace double quoted elements by single quotes
foreach($elements as $key => $element) {
$element = trim($element);
if (substr($element, 0, 1) == '"' &&
substr($element, -1, 1) == '"') {
$elements[$key] = "'" . trim($element, '"') . "'";
}
}
// Now call the standard $DB->sql_concat() DML function
return call_user_func_array(array($this->mdb, 'sql_concat'), $elements);
}
/**
* Returns the name (string) of the sequence used in the table for the autonumeric pk
* Only some DB have this implemented.
*
* @param xmldb_table $xmldb_table The xmldb_table instance.
* @return bool Returns the sequence from the DB or false.
*/
public function getSequenceFromDB($xmldb_table) {
return false;
}
/**
* Given one object name and it's type (pk, uk, fk, ck, ix, uix, seq, trg).
*
* (MySQL requires the whole xmldb_table object to be specified, so we add it always)
*
* This is invoked from getNameForObject().
* Only some DB have this implemented.
*
* @param string $object_name The object's name to check for.
* @param string $type The object's type (pk, uk, fk, ck, ix, uix, seq, trg).
* @param string $table_name The table's name to check in
* @return bool If such name is currently in use (true) or no (false)
*/
public function isNameInUse($object_name, $type, $table_name) {
return false; //For generators not implementing introspection,
//we always return with the name being free to be used
}
// ====== FOLLOWING FUNCTION MUST BE CUSTOMISED BY ALL THE XMLDGenerator classes ========
/**
* Reset a sequence to the id field of a table.
*
* @param xmldb_table|string $table name of table or the table object.
* @return array of sql statements
*/
public abstract function getResetSequenceSQL($table);
/**
* Given one correct xmldb_table, returns the SQL statements
* to create temporary table (inside one array).
*
* @param xmldb_table $xmldb_table The xmldb_table object instance.
* @return array of sql statements
*/
abstract public function getCreateTempTableSQL($xmldb_table);
/**
* Given one XMLDB Type, length and decimals, returns the DB proper SQL type.
*
* @param int $xmldb_type The xmldb_type defined constant. XMLDB_TYPE_INTEGER and other XMLDB_TYPE_* constants.
* @param int $xmldb_length The length of that data type.
* @param int $xmldb_decimals The decimal places of precision of the data type.
* @return string The DB defined data type.
*/
public abstract function getTypeSQL($xmldb_type, $xmldb_length=null, $xmldb_decimals=null);
/**
* Returns the code (array of statements) needed to execute extra statements on field rename.
*
* @param xmldb_table $xmldb_table The xmldb_table object instance.
* @param xmldb_field $xmldb_field The xmldb_field object instance.
* @return array Array of extra SQL statements to run with a field being renamed.
*/
public function getRenameFieldExtraSQL($xmldb_table, $xmldb_field) {
return array();
}
/**
* Returns the code (array of statements) needed
* to create one sequence for the xmldb_table and xmldb_field passed in.
*
* @param xmldb_table $xmldb_table The xmldb_table object instance.
* @param xmldb_field $xmldb_field The xmldb_field object instance.
* @return array Array of SQL statements to create the sequence.
*/
public function getCreateSequenceSQL($xmldb_table, $xmldb_field) {
return array();
}
/**
* Returns the code (array of statements) needed to add one comment to the table.
*
* @param xmldb_table $xmldb_table The xmldb_table object instance.
* @return array Array of SQL statements to add one comment to the table.
*/
public abstract function getCommentSQL($xmldb_table);
/**
* Returns the code (array of statements) needed to execute extra statements on table rename.
*
* @param xmldb_table $xmldb_table The xmldb_table object instance.
* @param string $newname The new name for the table.
* @return array Array of extra SQL statements to rename a table.
*/
public function getRenameTableExtraSQL($xmldb_table, $newname) {
return array();
}
/**
* Returns the code (array of statements) needed to execute extra statements on table drop
*
* @param xmldb_table $xmldb_table The xmldb_table object instance.
* @return array Array of extra SQL statements to drop a table.
*/
public function getDropTableExtraSQL($xmldb_table) {
return array();
}
/**
* Given one xmldb_table and one xmldb_field, return the SQL statements needed to drop its default
* (usually invoked from getModifyDefaultSQL()
*
* Note that this method may be dropped in future.
*
* @param xmldb_table $xmldb_table The xmldb_table object instance.
* @param xmldb_field $xmldb_field The xmldb_field object instance.
* @return array Array of SQL statements to create a field's default.
*
* @todo MDL-31147 Moodle 2.1 - Drop getDropDefaultSQL()
*/
public abstract function getDropDefaultSQL($xmldb_table, $xmldb_field);
/**
* Given one xmldb_table and one xmldb_field, return the SQL statements needed to add its default
* (usually invoked from getModifyDefaultSQL()
*
* @param xmldb_table $xmldb_table The xmldb_table object instance.
* @param xmldb_field $xmldb_field The xmldb_field object instance.
* @return array Array of SQL statements to create a field's default.
*/
public abstract function getCreateDefaultSQL($xmldb_table, $xmldb_field);
/**
* Returns an array of reserved words (lowercase) for this DB
* You MUST provide the real list for each DB inside every XMLDB class.
* @return array An array of database specific reserved words.
* @throws coding_exception Thrown if not implemented for the specific DB.
*/
public static function getReservedWords() {
throw new coding_exception('getReservedWords() method needs to be overridden in each subclass of sql_generator');
}
/**
* Returns all reserved words in supported databases.
* Reserved words should be lowercase.
* @return array ('word'=>array(databases))
*/
public static function getAllReservedWords() {
global $CFG;
$generators = array('mysql', 'postgres', 'oracle', 'mssql');
$reserved_words = array();
foreach($generators as $generator) {
$class = $generator . '_sql_generator';
require_once("$CFG->libdir/ddl/$class.php");
foreach (call_user_func(array($class, 'getReservedWords')) as $word) {
$reserved_words[$word][] = $generator;
}
}
ksort($reserved_words);
return $reserved_words;
}
/**
* Adds slashes to string.
* @param string $s
* @return string The escaped string.
*/
public function addslashes($s) {
// do not use php addslashes() because it depends on PHP quote settings!
$s = str_replace('\\','\\\\',$s);
$s = str_replace("\0","\\\0", $s);
$s = str_replace("'", "\\'", $s);
return $s;
}
/**
* Get the fields from an index definition that might be null.
* @param xmldb_table $xmldb_table the table
* @param xmldb_index $xmldb_index the index
* @return array list of fields in the index definition that might be null.
*/
public function get_nullable_fields_in_index($xmldb_table, $xmldb_index) {
global $DB;
// If we don't have the field info passed in, we need to query it from the DB.
$fieldsfromdb = null;
$nullablefields = [];
foreach ($xmldb_index->getFields() as $fieldname) {
if ($field = $xmldb_table->getField($fieldname)) {
// We have the field details in the table definition.
if ($field->getNotNull() !== XMLDB_NOTNULL) {
$nullablefields[] = $fieldname;
}
} else {
// We don't have the table definition loaded. Need to
// inspect the database.
if ($fieldsfromdb === null) {
$fieldsfromdb = $DB->get_columns($xmldb_table->getName(), false);
}
if (!isset($fieldsfromdb[$fieldname])) {
throw new coding_exception('Unknown field ' . $fieldname .
' in index ' . $xmldb_index->getName());
}
if (!$fieldsfromdb[$fieldname]->not_null) {
$nullablefields[] = $fieldname;
}
}
}
return $nullablefields;
}
}