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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/>.
/**
* PostgreSQL specific SQL code generator.
*
* @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();
require_once($CFG->libdir.'/ddl/sql_generator.php');
/**
* This class generate SQL code to be used against PostgreSQL
* It extends XMLDBgenerator so everything can 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
*/
class postgres_sql_generator extends sql_generator {
// Only set values that are different from the defaults present in XMLDBgenerator
/** @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 = '';
/** @var bool True if the generator needs to add extra code to generate the sequence fields.*/
public $sequence_extra_code = false;
/** @var string The particular name for inline sequences in this generator.*/
public $sequence_name = 'BIGSERIAL';
/** @var string The particular name for inline sequences in this generator.*/
public $sequence_name_small = 'SERIAL';
/** @var bool To avoid outputting the rest of the field specs, leaving only the name and the sequence_name returned.*/
public $sequence_only = true;
/** @var string SQL sentence to rename one index where 'TABLENAME', 'OLDINDEXNAME' and 'NEWINDEXNAME' are dynamically replaced.*/
public $rename_index_sql = 'ALTER TABLE OLDINDEXNAME RENAME TO NEWINDEXNAME';
/** @var string SQL sentence to rename one key 'TABLENAME', 'OLDKEYNAME' and 'NEWKEYNAME' are dynamically replaced.*/
public $rename_key_sql = null;
/** @var string type of string quoting used - '' or \' quotes*/
protected $std_strings = null;
/**
* Reset a sequence to the id field of a table.
*
* @param xmldb_table|string $table name of table or the table object.
* @return array of sql statements
*/
public function getResetSequenceSQL($table) {
if ($table instanceof xmldb_table) {
$tablename = $table->getName();
} else {
$tablename = $table;
}
// From http://www.postgresql.org/docs/7.4/static/sql-altersequence.html
$value = (int)$this->mdb->get_field_sql('SELECT MAX(id) FROM {'.$tablename.'}');
$value++;
return array("ALTER SEQUENCE $this->prefix{$tablename}_id_seq RESTART WITH $value");
}
/**
* Given one correct xmldb_table, returns the SQL statements
* to create temporary table (inside one array).
*
* @param xmldb_table $xmldb_table The xmldb_table object instance.
* @return array of sql statements
*/
public function getCreateTempTableSQL($xmldb_table) {
$this->temptables->add_temptable($xmldb_table->getName());
$sqlarr = $this->getCreateTableSQL($xmldb_table);
$sqlarr = preg_replace('/^CREATE TABLE/', "CREATE TEMPORARY TABLE", $sqlarr);
return $sqlarr;
}
/**
* 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) {
$sqls = parent::getCreateIndexSQL($xmldb_table, $xmldb_index);
$hints = $xmldb_index->getHints();
$fields = $xmldb_index->getFields();
if (in_array('varchar_pattern_ops', $hints) and count($fields) == 1) {
// Add the pattern index and keep the normal one, keep unique only the standard index to improve perf.
foreach ($sqls as $sql) {
$field = reset($fields);
$count = 0;
$newindex = preg_replace("/^CREATE( UNIQUE)? INDEX ([a-z0-9_]+) ON ([a-z0-9_]+) \($field\)$/", "CREATE INDEX \\2_pattern ON \\3 USING btree ($field varchar_pattern_ops)", $sql, -1, $count);
if ($count != 1) {
debugging('Unexpected getCreateIndexSQL() structure.');
continue;
}
$sqls[] = $newindex;
}
}
return $sqls;
}
/**
* 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 $xmldb_decimals The decimal places of precision of the data type.
* @return string The DB defined data type.
*/
public function getTypeSQL($xmldb_type, $xmldb_length=null, $xmldb_decimals=null) {
switch ($xmldb_type) {
case XMLDB_TYPE_INTEGER: // From http://www.postgresql.org/docs/7.4/interactive/datatype.html
if (empty($xmldb_length)) {
$xmldb_length = 10;
}
if ($xmldb_length > 9) {
$dbtype = 'BIGINT';
} else if ($xmldb_length > 4) {
$dbtype = 'INTEGER';
} else {
$dbtype = 'SMALLINT';
}
break;
case XMLDB_TYPE_NUMBER:
$dbtype = $this->number_type;
if (!empty($xmldb_length)) {
$dbtype .= '(' . $xmldb_length;
if (!empty($xmldb_decimals)) {
$dbtype .= ',' . $xmldb_decimals;
}
$dbtype .= ')';
}
break;
case XMLDB_TYPE_FLOAT:
$dbtype = 'DOUBLE PRECISION';
if (!empty($xmldb_decimals)) {
if ($xmldb_decimals < 6) {
$dbtype = 'REAL';
}
}
break;
case XMLDB_TYPE_CHAR:
$dbtype = 'VARCHAR';
if (empty($xmldb_length)) {
$xmldb_length='255';
}
$dbtype .= '(' . $xmldb_length . ')';
break;
case XMLDB_TYPE_TEXT:
$dbtype = 'TEXT';
break;
case XMLDB_TYPE_BINARY:
$dbtype = 'BYTEA';
break;
case XMLDB_TYPE_DATETIME:
$dbtype = 'TIMESTAMP';
break;
}
return $dbtype;
}
/**
* Returns the code (array of statements) needed to add one comment to the table.
*
* @param xmldb_table $xmldb_table The xmldb_table object instance.
* @return array Array of SQL statements to add one comment to the table.
*/
function getCommentSQL ($xmldb_table) {
$comment = "COMMENT ON TABLE " . $this->getTableName($xmldb_table);
$comment.= " IS '" . $this->addslashes(substr($xmldb_table->getComment(), 0, 250)) . "'";
return array($comment);
}
/**
* 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) {
$results = array();
$newt = new xmldb_table($newname);
$xmldb_field = new xmldb_field('id'); // Fields having sequences should be exclusively, id.
$oldseqname = $this->getTableName($xmldb_table) . '_' . $xmldb_field->getName() . '_seq';
$newseqname = $this->getTableName($newt) . '_' . $xmldb_field->getName() . '_seq';
// Rename de sequence
$results[] = 'ALTER TABLE ' . $oldseqname . ' RENAME TO ' . $newseqname;
return $results;
}
/**
* Given one xmldb_table and one xmldb_field, return the SQL statements needed to alter the field in the table.
*
* PostgreSQL has some severe limits:
* - Any change of type or precision requires a new temporary column to be created, values to
* be transfered potentially casting them, to apply defaults if the column is not null and
* finally, to rename it
* - Changes in null/not null require the SET/DROP NOT NULL clause
* - Changes in default require the SET/DROP DEFAULT clause
*
* @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) {
$results = array(); // To store all the needed SQL commands
// Get the normal names of the table and field
$tablename = $xmldb_table->getName();
$fieldname = $xmldb_field->getName();
// Take a look to field metadata
$meta = $this->mdb->get_columns($tablename);
$metac = $meta[$xmldb_field->getName()];
$oldmetatype = $metac->meta_type;
$oldlength = $metac->max_length;
$olddecimals = empty($metac->scale) ? null : $metac->scale;
$oldnotnull = empty($metac->not_null) ? false : $metac->not_null;
$olddefault = empty($metac->has_default) ? null : $metac->default_value;
$typechanged = true; //By default, assume that the column type has changed
$precisionchanged = true; //By default, assume that the column precision has changed
$decimalchanged = true; //By default, assume that the column decimal has changed
$defaultchanged = true; //By default, assume that the column default has changed
$notnullchanged = true; //By default, assume that the column notnull has changed
// Detect if we are changing the type of the column
if (($xmldb_field->getType() == XMLDB_TYPE_INTEGER && $oldmetatype == 'I') ||
($xmldb_field->getType() == XMLDB_TYPE_NUMBER && $oldmetatype == 'N') ||
($xmldb_field->getType() == XMLDB_TYPE_FLOAT && $oldmetatype == 'F') ||
($xmldb_field->getType() == XMLDB_TYPE_CHAR && $oldmetatype == 'C') ||
($xmldb_field->getType() == XMLDB_TYPE_TEXT && $oldmetatype == 'X') ||
($xmldb_field->getType() == XMLDB_TYPE_BINARY && $oldmetatype == 'B')) {
$typechanged = false;
}
// Detect if we are changing the precision
if (($xmldb_field->getType() == XMLDB_TYPE_TEXT) ||
($xmldb_field->getType() == XMLDB_TYPE_BINARY) ||
($oldlength == -1) ||
($xmldb_field->getLength() == $oldlength)) {
$precisionchanged = false;
}
// Detect if we are changing the decimals
if (($xmldb_field->getType() == XMLDB_TYPE_INTEGER) ||
($xmldb_field->getType() == XMLDB_TYPE_CHAR) ||
($xmldb_field->getType() == XMLDB_TYPE_TEXT) ||
($xmldb_field->getType() == XMLDB_TYPE_BINARY) ||
(!$xmldb_field->getDecimals()) ||
(!$olddecimals) ||
($xmldb_field->getDecimals() == $olddecimals)) {
$decimalchanged = false;
}
// Detect if we are changing the default
if (($xmldb_field->getDefault() === null && $olddefault === null) ||
($xmldb_field->getDefault() === $olddefault)) {
$defaultchanged = false;
}
// Detect if we are changing the nullability
if (($xmldb_field->getNotnull() === $oldnotnull)) {
$notnullchanged = false;
}
// Get the quoted name of the table and field
$tablename = $this->getTableName($xmldb_table);
$fieldname = $this->getEncQuoted($xmldb_field->getName());
// Decide if we have changed the column specs (type/precision/decimals)
$specschanged = $typechanged || $precisionchanged || $decimalchanged;
// if specs have changed, need to alter column
if ($specschanged) {
// Always drop any exiting default before alter column (some type changes can cause casting error in default for column)
if ($olddefault !== null) {
$results[] = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' DROP DEFAULT'; // Drop default clause
}
$alterstmt = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $this->getEncQuoted($xmldb_field->getName()) .
' TYPE' . $this->getFieldSQL($xmldb_table, $xmldb_field, null, true, true, null, false);
// Some castings must be performed explicitly (mainly from text|char to numeric|integer)
if (($oldmetatype == 'C' || $oldmetatype == 'X') &&
($xmldb_field->getType() == XMLDB_TYPE_NUMBER || $xmldb_field->getType() == XMLDB_TYPE_FLOAT)) {
$alterstmt .= ' USING CAST('.$fieldname.' AS NUMERIC)'; // from char or text to number or float
} else if (($oldmetatype == 'C' || $oldmetatype == 'X') &&
$xmldb_field->getType() == XMLDB_TYPE_INTEGER) {
$alterstmt .= ' USING CAST(CAST('.$fieldname.' AS NUMERIC) AS INTEGER)'; // From char to integer
}
$results[] = $alterstmt;
}
// If the default has changed or we have performed one change in specs
if ($defaultchanged || $specschanged) {
$default_clause = $this->getDefaultClause($xmldb_field);
if ($default_clause) {
$sql = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' SET' . $default_clause; // Add default clause
$results[] = $sql;
} else {
if (!$specschanged) { // Only drop default if we haven't performed one specs change
$results[] = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' DROP DEFAULT'; // Drop default clause
}
}
}
// If the not null has changed
if ($notnullchanged) {
if ($xmldb_field->getNotnull()) {
$results[] = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' SET NOT NULL';
} else {
$results[] = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' DROP NOT NULL';
}
}
// Return the results
return $results;
}
/**
* 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 $xmldb_field The xmldb_field object instance.
* @return array Array of SQL statements to create a field's default.
*/
public function getCreateDefaultSQL($xmldb_table, $xmldb_field) {
// Just a wrapper over the getAlterFieldSQL() function for PostgreSQL that
// is capable of handling defaults
return $this->getAlterFieldSQL($xmldb_table, $xmldb_field);
}
/**
* 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 $xmldb_field The xmldb_field object instance.
* @return array Array of SQL statements to create a field's default.
*
* @todo MDL-31147 Moodle 2.1 - Drop getDropDefaultSQL()
*/
public function getDropDefaultSQL($xmldb_table, $xmldb_field) {
// Just a wrapper over the getAlterFieldSQL() function for PostgreSQL that
// is capable of handling defaults
return $this->getAlterFieldSQL($xmldb_table, $xmldb_field);
}
/**
* Adds slashes to string.
* @param string $s
* @return string The escaped string.
*/
public function addslashes($s) {
// Postgres is gradually switching to ANSI quotes, we need to check what is expected
if (!isset($this->std_strings)) {
$this->std_strings = ($this->mdb->get_field_sql("select setting from pg_settings where name = 'standard_conforming_strings'") === 'on');
}
if ($this->std_strings) {
$s = str_replace("'", "''", $s);
} else {
// 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;
}
/**
* Given one xmldb_table returns one string with the sequence of the table
* in the table (fetched from DB)
* The sequence name for Postgres has one standard name convention:
* tablename_fieldname_seq
* so we just calculate it and confirm it's present in pg_class
*
* @param xmldb_table $xmldb_table The xmldb_table object instance.
* @return string|bool If no sequence is found, returns false
*/
function getSequenceFromDB($xmldb_table) {
$tablename = $this->getTableName($xmldb_table);
$sequencename = $tablename . '_id_seq';
if (!$this->mdb->get_record_sql("SELECT c.*
FROM pg_catalog.pg_class c
JOIN pg_catalog.pg_namespace as ns ON ns.oid = c.relnamespace
WHERE c.relname = ? AND c.relkind = 'S'
AND (ns.nspname = current_schema() OR ns.oid = pg_my_temp_schema())",
array($sequencename))) {
$sequencename = false;
}
return $sequencename;
}
/**
* 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, $table_name) {
switch($type) {
case 'ix':
case 'uix':
case 'seq':
if ($check = $this->mdb->get_records_sql("SELECT c.relname
FROM pg_class c
JOIN pg_catalog.pg_namespace as ns ON ns.oid = c.relnamespace
WHERE lower(c.relname) = ?
AND (ns.nspname = current_schema() OR ns.oid = pg_my_temp_schema())", array(strtolower($object_name)))) {
return true;
}
break;
case 'pk':
case 'uk':
case 'fk':
case 'ck':
if ($check = $this->mdb->get_records_sql("SELECT c.conname
FROM pg_constraint c
JOIN pg_catalog.pg_namespace as ns ON ns.oid = c.connamespace
WHERE lower(c.conname) = ?
AND (ns.nspname = current_schema() OR ns.oid = pg_my_temp_schema())", array(strtolower($object_name)))) {
return true;
}
break;
case 'trg':
if ($check = $this->mdb->get_records_sql("SELECT tgname
FROM pg_trigger
WHERE lower(tgname) = ?", array(strtolower($object_name)))) {
return true;
}
break;
}
return false; //No name in use found
}
/**
* Returns an array of reserved words (lowercase) for this DB
* @return array An array of database specific reserved words
*/
public static function getReservedWords() {
// This file contains the reserved words for PostgreSQL databases
// This file contains the reserved words for PostgreSQL databases
// http://www.postgresql.org/docs/current/static/sql-keywords-appendix.html
$reserved_words = array (
'all', 'analyse', 'analyze', 'and', 'any', 'array', 'as', 'asc',
'asymmetric', 'authorization', 'between', 'binary', 'both', 'case',
'cast', 'check', 'collate', 'column', 'constraint', 'create', 'cross',
'current_date', 'current_role', 'current_time', 'current_timestamp',
'current_user', 'default', 'deferrable', 'desc', 'distinct', 'do',
'else', 'end', 'except', 'false', 'for', 'foreign', 'freeze', 'from',
'full', 'grant', 'group', 'having', 'ilike', 'in', 'initially', 'inner',
'intersect', 'into', 'is', 'isnull', 'join', 'leading', 'left', 'like',
'limit', 'localtime', 'localtimestamp', 'natural', 'new', 'not',
'notnull', 'null', 'off', 'offset', 'old', 'on', 'only', 'or', 'order',
'outer', 'overlaps', 'placing', 'primary', 'references', 'returning', 'right', 'select',
'session_user', 'similar', 'some', 'symmetric', 'table', 'then', 'to',
'trailing', 'true', 'union', 'unique', 'user', 'using', 'verbose',
'when', 'where', 'with'
);
return $reserved_words;
}
}