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Developer Documentation
- Bug fixes for general core bugs in 4.3.x will end 7 October 2024 (12 months).
- Bug fixes for security issues in 4.3.x will end 21 April 2025 (18 months).
- PHP version: minimum PHP 8.0.0 Note: minimum PHP version has increased since Moodle 4.1. PHP 8.2.x is supported too.
/lib/dml/ -> moodle_database.php (source)
Differences Between: [Versions 310 and 403] [Versions 311 and 403] [Versions 39 and 403] [Versions 400 and 403] [Versions 401 and 403] [Versions 402 and 403]
Abstract database driver class.
| Copyright: | 2008 Petr Skoda (http://skodak.org) |
| License: | http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later |
| File Size: | 2910 lines (120 kb) |
| Included or required: | 8 times |
| Referenced: | 0 times |
| Includes or requires: | 4 files lib/testing/classes/util.php lib/dml/moodle_transaction.php lib/dml/moodle_recordset.php lib/dml/database_column_info.php |
Defines 1 class
moodle_database:: (118 methods):
__construct()
__destruct()
get_prefix()
get_driver_instance()
get_dbvendor()
get_configuration_hints()
export_dbconfig()
diagnose()
store_settings()
get_settings_hash()
get_metacache()
get_temp_tables_cache()
create_database()
get_transaction_start_backtrace()
dispose()
query_start()
query_end()
query_log()
query_log_prevent()
query_log_allow()
query_time()
print_debug()
print_debug_time()
where_clause()
where_clause_list()
get_in_or_equal()
fix_table_names()
fix_table_name()
_fix_sql_params_dollar_callback()
detect_objects()
fix_sql_params()
add_sql_debugging()
normalise_limit_from_num()
get_columns()
reset_caches()
get_manager()
change_db_encoding()
setup_is_unicodedb()
set_debug()
get_debug()
set_logging()
get_recordset()
get_recordset_list()
get_recordset_select()
export_table_recordset()
get_records()
get_records_list()
get_records_select()
get_records_menu()
get_records_select_menu()
get_records_sql_menu()
get_record()
get_record_select()
get_record_sql()
get_field()
get_field_select()
get_field_sql()
get_fieldset_select()
insert_records()
set_field()
count_records()
count_records_select()
count_records_sql()
record_exists()
record_exists_select()
record_exists_sql()
delete_records()
delete_records_list()
delete_records_subquery()
sql_null_from_clause()
sql_bitand()
sql_bitnot()
sql_bitor()
sql_bitxor()
sql_modulo()
sql_ceil()
sql_cast_to_char()
sql_cast_char2int()
sql_cast_char2real()
sql_cast_2signed()
sql_compare_text()
sql_equal()
sql_like()
sql_like_escape()
sql_fullname()
sql_order_by_text()
sql_order_by_null()
sql_length()
sql_substr()
sql_position()
sql_empty()
sql_isempty()
sql_isnotempty()
sql_regex_supported()
sql_regex()
sql_regex_get_word_beginning_boundary_marker()
sql_regex_get_word_end_boundary_marker()
sql_intersect()
replace_all_text_supported()
replace_all_text()
update_temp_table_stats()
transactions_supported()
is_transaction_started()
transactions_forbidden()
start_delegated_transaction()
commit_delegated_transaction()
rollback_delegated_transaction()
force_transaction_rollback()
session_lock_supported()
get_session_lock()
release_session_lock()
perf_get_reads()
want_read_slave()
perf_get_reads_slave()
perf_get_writes()
perf_get_queries()
perf_get_queries_time()
is_fulltext_search_supported()
Class: moodle_database - X-Ref
Abstract class representing moodle database interface.| __construct($external=false) X-Ref |
| Constructor - Instantiates the database, specifying if it's external (connect to other systems) or not (Moodle DB). Note that this affects the decision of whether prefix checks must be performed or not. param: bool $external True means that an external database is used. |
| __destruct() X-Ref |
| Destructor - cleans up and flushes everything needed. |
| get_prefix() X-Ref |
| Returns database table prefix Note: can be used before connect() return: string The prefix used in the database. |
| get_driver_instance($type, $library, $external = false) X-Ref |
| Loads and returns a database instance with the specified type and library. The loaded class is within lib/dml directory and of the form: $type.'_'.$library.'_moodle_database' param: string $type Database driver's type. (eg: mysqli, pgsql, mssql, sqldrv, oci, etc.) param: string $library Database driver's library (native, pdo, etc.) param: bool $external True if this is an external database. return: moodle_database driver object or null if error, for example of driver object see {@link mysqli_native_moodle_database} |
| get_dbvendor() X-Ref |
| Returns the database vendor. Note: can be used before connect() return: string The db vendor name, usually the same as db family name. |
| get_configuration_hints() X-Ref |
| Returns the localised database description Note: can be used before connect() return: string |
| export_dbconfig() X-Ref |
| Returns the db related part of config.php return: stdClass |
| diagnose() X-Ref |
| Diagnose database and tables, this function is used to verify database and driver settings, db engine types, etc. return: string null means everything ok, string means problem found. |
| store_settings($dbhost, $dbuser, $dbpass, $dbname, $prefix, array $dboptions=null) X-Ref |
| Store various database settings param: string $dbhost The database host. param: string $dbuser The database user to connect as. param: string $dbpass The password to use when connecting to the database. param: string $dbname The name of the database being connected to. param: mixed $prefix string means moodle db prefix, false used for external databases where prefix not used param: array $dboptions driver specific options return: void |
| get_settings_hash() X-Ref |
| Returns a hash for the settings used during connection. If not already requested it is generated and stored in a private property. return: string |
| get_metacache() X-Ref |
| Handle the creation and caching of the databasemeta information for all databases. return: cache_application The databasemeta cachestore to complete operations on. |
| get_temp_tables_cache() X-Ref |
| Handle the creation and caching of the temporary tables. return: cache_application The temp_tables cachestore to complete operations on. |
| create_database($dbhost, $dbuser, $dbpass, $dbname, array $dboptions=null) X-Ref |
| Attempt to create the database param: string $dbhost The database host. param: string $dbuser The database user to connect as. param: string $dbpass The password to use when connecting to the database. param: string $dbname The name of the database being connected to. param: array $dboptions An array of optional database options (eg: dbport) return: bool success True for successful connection. False otherwise. |
| get_transaction_start_backtrace() X-Ref |
| Returns transaction trace for debugging purposes. return: array or null if not in transaction. |
| dispose() X-Ref |
| Closes the database connection and releases all resources and memory (especially circular memory references). Do NOT use connect() again, create a new instance if needed. return: void |
| query_start($sql, ?array $params, $type, $extrainfo=null) X-Ref |
| This should be called before each db query. param: string $sql The query string. param: array|null $params An array of parameters. param: int $type The type of query ( SQL_QUERY_SELECT | SQL_QUERY_AUX_READONLY | SQL_QUERY_AUX | param: mixed $extrainfo This is here for any driver specific extra information. return: void |
| query_end($result) X-Ref |
| This should be called immediately after each db query. It does a clean up of resources. It also throws exceptions if the sql that ran produced errors. param: mixed $result The db specific result obtained from running a query. return: void |
| query_log($error=false) X-Ref |
| This logs the last query based on 'logall', 'logslow' and 'logerrors' options configured via $CFG->dboptions . param: string|bool $error or false if not error return: void |
| query_log_prevent() X-Ref |
| Disable logging temporarily. |
| query_log_allow() X-Ref |
| Restore old logging behavior. |
| query_time() X-Ref |
| Returns the time elapsed since the query started. return: float Seconds with microseconds |
| print_debug($sql, array $params=null, $obj=null) X-Ref |
| Prints sql debug info param: string $sql The query which is being debugged. param: array $params The query parameters. (optional) param: mixed $obj The library specific object. (optional) return: void |
| print_debug_time() X-Ref |
| Prints the time a query took to run. return: void |
| where_clause($table, array $conditions=null) X-Ref |
| Returns the SQL WHERE conditions. param: string $table The table name that these conditions will be validated against. param: array $conditions The conditions to build the where clause. (must not contain numeric indexes) return: array An array list containing sql 'where' part and 'params'. |
| where_clause_list($field, array $values) X-Ref |
| Returns SQL WHERE conditions for the ..._list group of methods. param: string $field the name of a field. param: array $values the values field might take. return: array An array containing sql 'where' part and 'params' |
| get_in_or_equal($items, $type=SQL_PARAMS_QM, $prefix='param', $equal=true, $onemptyitems=false) X-Ref |
| Constructs 'IN()' or '=' sql fragment param: mixed $items A single value or array of values for the expression. param: int $type Parameter bounding type : SQL_PARAMS_QM or SQL_PARAMS_NAMED. param: string $prefix Named parameter placeholder prefix (a unique counter value is appended to each parameter name). param: bool $equal True means we want to equate to the constructed expression, false means we don't want to equate to it. param: mixed $onemptyitems This defines the behavior when the array of items provided is empty. Defaults to false, return: array A list containing the constructed sql fragment and an array of parameters. |
| fix_table_names($sql) X-Ref |
| Converts short table name {tablename} to the real prefixed table name in given sql. param: string $sql The sql to be operated on. return: string The sql with tablenames being prefixed with $CFG->prefix |
| fix_table_name($tablename) X-Ref |
| No description |
| _fix_sql_params_dollar_callback($match) X-Ref |
| Internal private utitlity function used to fix parameters. Used with {@link preg_replace_callback()} param: array $match Refer to preg_replace_callback usage for description. return: string |
| detect_objects($value) X-Ref |
| Detects object parameters and throws exception if found param: mixed $value return: void |
| fix_sql_params($sql, array $params=null) X-Ref |
| Normalizes sql query parameters and verifies parameters. param: string $sql The query or part of it. param: array $params The query parameters. return: array (sql, params, type of params) |
| add_sql_debugging(string $sql) X-Ref |
| Add an SQL comment to trace all sql calls back to the calling php code param: string $sql Original sql return: string Instrumented sql |
| normalise_limit_from_num($limitfrom, $limitnum) X-Ref |
| Ensures that limit params are numeric and positive integers, to be passed to the database. We explicitly treat null, '' and -1 as 0 in order to provide compatibility with how limit values have been passed historically. param: int $limitfrom Where to start results from param: int $limitnum How many results to return return: array Normalised limit params in array($limitfrom, $limitnum) |
| get_columns($table, $usecache = true) X-Ref |
| Returns detailed information about columns in table. This information is cached internally. param: string $table The table's name. param: bool $usecache Flag to use internal cacheing. The default is true. return: database_column_info[] of database_column_info objects indexed with column names |
| reset_caches($tablenames = null) X-Ref |
| Resets the internal column details cache param: array|null $tablenames an array of xmldb table names affected by this request. return: void |
| get_manager() X-Ref |
| Returns the sql generator used for db manipulation. Used mostly in upgrade.php scripts. return: database_manager The instance used to perform ddl operations. |
| change_db_encoding() X-Ref |
| Attempts to change db encoding to UTF-8 encoding if possible. return: bool True is successful. |
| setup_is_unicodedb() X-Ref |
| Checks to see if the database is in unicode mode? return: bool |
| set_debug($state) X-Ref |
| Enable/disable very detailed debugging. param: bool $state return: void |
| get_debug() X-Ref |
| Returns debug status return: bool $state |
| set_logging($state) X-Ref |
| Enable/disable detailed sql logging |
| get_recordset($table, array $conditions=null, $sort='', $fields='*', $limitfrom=0, $limitnum=0) X-Ref |
| Get a number of records as a moodle_recordset where all the given conditions met. Selects records from the table $table. If specified, only records meeting $conditions. If specified, the results will be sorted as specified by $sort. This is added to the SQL as "ORDER BY $sort". Example values of $sort might be "time ASC" or "time DESC". If $fields is specified, only those fields are returned. Since this method is a little less readable, use of it should be restricted to code where it's possible there might be large datasets being returned. For known small datasets use get_records - it leads to simpler code. If you only want some of the records, specify $limitfrom and $limitnum. The query will skip the first $limitfrom records (according to the sort order) and then return the next $limitnum records. If either of $limitfrom or $limitnum is specified, both must be present. The return value is a moodle_recordset if the query succeeds. If an error occurs, false is returned. param: string $table the table to query. param: array $conditions optional array $fieldname=>requestedvalue with AND in between param: string $sort an order to sort the results in (optional, a valid SQL ORDER BY parameter). param: string $fields a comma separated list of fields to return (optional, by default all fields are returned). param: int $limitfrom return a subset of records, starting at this point (optional). param: int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set). return: moodle_recordset A moodle_recordset instance |
| get_recordset_list($table, $field, array $values, $sort='', $fields='*', $limitfrom=0, $limitnum=0) X-Ref |
| Get a number of records as a moodle_recordset where one field match one list of values. Only records where $field takes one of the values $values are returned. $values must be an array of values. Other arguments and the return type are like {@link function get_recordset}. param: string $table the table to query. param: string $field a field to check (optional). param: array $values array of values the field must have param: string $sort an order to sort the results in (optional, a valid SQL ORDER BY parameter). param: string $fields a comma separated list of fields to return (optional, by default all fields are returned). param: int $limitfrom return a subset of records, starting at this point (optional). param: int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set). return: moodle_recordset A moodle_recordset instance. |
| get_recordset_select($table, $select, array $params=null, $sort='', $fields='*', $limitfrom=0, $limitnum=0) X-Ref |
| Get a number of records as a moodle_recordset which match a particular WHERE clause. If given, $select is used as the SELECT parameter in the SQL query, otherwise all records from the table are returned. Other arguments and the return type are like {@link function get_recordset}. param: string $table the table to query. param: string $select A fragment of SQL to be used in a where clause in the SQL call. param: array $params array of sql parameters param: string $sort an order to sort the results in (optional, a valid SQL ORDER BY parameter). param: string $fields a comma separated list of fields to return (optional, by default all fields are returned). param: int $limitfrom return a subset of records, starting at this point (optional). param: int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set). return: moodle_recordset A moodle_recordset instance. |
| export_table_recordset($table) X-Ref |
| Get all records from a table. This method works around potential memory problems and may improve performance, this method may block access to table until the recordset is closed. param: string $table Name of database table. return: moodle_recordset A moodle_recordset instance {@link function get_recordset}. |
| get_records($table, array $conditions=null, $sort='', $fields='*', $limitfrom=0, $limitnum=0) X-Ref |
| Get a number of records as an array of objects where all the given conditions met. If the query succeeds and returns at least one record, the return value is an array of objects, one object for each record found. The array key is the value from the first column of the result set. The object associated with that key has a member variable for each column of the results. param: string $table the table to query. param: array $conditions optional array $fieldname=>requestedvalue with AND in between param: string $sort an order to sort the results in (optional, a valid SQL ORDER BY parameter). param: string $fields a comma separated list of fields to return (optional, by default param: int $limitfrom return a subset of records, starting at this point (optional). param: int $limitnum return a subset comprising this many records in total (optional, required if $limitfrom is set). return: array An array of Objects indexed by first column. |
| get_records_list($table, $field, array $values, $sort='', $fields='*', $limitfrom=0, $limitnum=0) X-Ref |
| Get a number of records as an array of objects where one field match one list of values. Return value is like {@link function get_records}. param: string $table The database table to be checked against. param: string $field The field to search param: array $values An array of values param: string $sort Sort order (as valid SQL sort parameter) param: string $fields A comma separated list of fields to be returned from the chosen table. If specified, param: int $limitfrom return a subset of records, starting at this point (optional). param: int $limitnum return a subset comprising this many records in total (optional). return: array An array of objects indexed by first column |
| get_records_select($table, $select, array $params=null, $sort='', $fields='*', $limitfrom=0, $limitnum=0) X-Ref |
| Get a number of records as an array of objects which match a particular WHERE clause. Return value is like {@link function get_records}. param: string $table The table to query. param: string $select A fragment of SQL to be used in a where clause in the SQL call. param: array $params An array of sql parameters param: string $sort An order to sort the results in (optional, a valid SQL ORDER BY parameter). param: string $fields A comma separated list of fields to return param: int $limitfrom return a subset of records, starting at this point (optional). param: int $limitnum return a subset comprising this many records in total (optional, required if $limitfrom is set). return: array of objects indexed by first column |
| get_records_menu($table, array $conditions=null, $sort='', $fields='*', $limitfrom=0, $limitnum=0) X-Ref |
| Get the first two columns from a number of records as an associative array where all the given conditions met. Arguments are like {@link function get_recordset}. If no errors occur the return value is an associative whose keys come from the first field of each record, and whose values are the corresponding second fields. False is returned if an error occurs. param: string $table the table to query. param: array $conditions optional array $fieldname=>requestedvalue with AND in between param: string $sort an order to sort the results in (optional, a valid SQL ORDER BY parameter). param: string $fields a comma separated list of fields to return - the number of fields should be 2! param: int $limitfrom return a subset of records, starting at this point (optional). param: int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set). return: array an associative array |
| get_records_select_menu($table, $select, array $params=null, $sort='', $fields='*', $limitfrom=0, $limitnum=0) X-Ref |
| Get the first two columns from a number of records as an associative array which match a particular WHERE clause. Arguments are like {@link function get_recordset_select}. Return value is like {@link function get_records_menu}. param: string $table The database table to be checked against. param: string $select A fragment of SQL to be used in a where clause in the SQL call. param: array $params array of sql parameters param: string $sort Sort order (optional) - a valid SQL order parameter param: string $fields A comma separated list of fields to be returned from the chosen table - the number of fields should be 2! param: int $limitfrom return a subset of records, starting at this point (optional). param: int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set). return: array an associative array |
| get_records_sql_menu($sql, array $params=null, $limitfrom=0, $limitnum=0) X-Ref |
| Get the first two columns from a number of records as an associative array using a SQL statement. Arguments are like {@link function get_recordset_sql}. Return value is like {@link function get_records_menu}. param: string $sql The SQL string you wish to be executed. param: array $params array of sql parameters param: int $limitfrom return a subset of records, starting at this point (optional). param: int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set). return: array an associative array |
| get_record($table, array $conditions, $fields='*', $strictness=IGNORE_MISSING) X-Ref |
| Get a single database record as an object where all the given conditions met. param: string $table The table to select from. param: array $conditions optional array $fieldname=>requestedvalue with AND in between param: string $fields A comma separated list of fields to be returned from the chosen table. param: int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found; return: mixed a fieldset object containing the first matching record, false or exception if error not found depending on mode |
| get_record_select($table, $select, array $params=null, $fields='*', $strictness=IGNORE_MISSING) X-Ref |
| Get a single database record as an object which match a particular WHERE clause. param: string $table The database table to be checked against. param: string $select A fragment of SQL to be used in a where clause in the SQL call. param: array $params array of sql parameters param: string $fields A comma separated list of fields to be returned from the chosen table. param: int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found; return: stdClass|false a fieldset object containing the first matching record, false or exception if error not found depending on mode |
| get_record_sql($sql, array $params=null, $strictness=IGNORE_MISSING) X-Ref |
| Get a single database record as an object using a SQL statement. The SQL statement should normally only return one record. It is recommended to use get_records_sql() if more matches possible! param: string $sql The SQL string you wish to be executed, should normally only return one record. param: array $params array of sql parameters param: int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found; return: mixed a fieldset object containing the first matching record, false or exception if error not found depending on mode |
| get_field($table, $return, array $conditions, $strictness=IGNORE_MISSING) X-Ref |
| Get a single field value from a table record where all the given conditions met. param: string $table the table to query. param: string $return the field to return the value of. param: array $conditions optional array $fieldname=>requestedvalue with AND in between param: int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found; return: mixed the specified value false if not found |
| get_field_select($table, $return, $select, array $params=null, $strictness=IGNORE_MISSING) X-Ref |
| Get a single field value from a table record which match a particular WHERE clause. param: string $table the table to query. param: string $return the field to return the value of. param: string $select A fragment of SQL to be used in a where clause returning one row with one column param: array $params array of sql parameters param: int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found; return: mixed the specified value false if not found |
| get_field_sql($sql, array $params=null, $strictness=IGNORE_MISSING) X-Ref |
| Get a single field value (first field) using a SQL statement. param: string $sql The SQL query returning one row with one column param: array $params array of sql parameters param: int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found; return: mixed the specified value false if not found |
| get_fieldset_select($table, $return, $select, array $params=null) X-Ref |
| Selects records and return values of chosen field as an array which match a particular WHERE clause. param: string $table the table to query. param: string $return the field we are intered in param: string $select A fragment of SQL to be used in a where clause in the SQL call. param: array $params array of sql parameters return: array of values |
| insert_records($table, $dataobjects) X-Ref |
| Insert multiple records into database as fast as possible. Order of inserts is maintained, but the operation is not atomic, use transactions if necessary. This method is intended for inserting of large number of small objects, do not use for huge objects with text or binary fields. param: string $table The database table to be inserted into param: array|Traversable $dataobjects list of objects to be inserted, must be compatible with foreach return: void does not return new record ids |
| set_field($table, $newfield, $newvalue, array $conditions=null) X-Ref |
| Set a single field in every table record where all the given conditions met. param: string $table The database table to be checked against. param: string $newfield the field to set. param: mixed $newvalue the value to set the field to. param: array $conditions optional array $fieldname=>requestedvalue with AND in between return: bool true |
| count_records($table, array $conditions=null) X-Ref |
| Count the records in a table where all the given conditions met. param: string $table The table to query. param: array $conditions optional array $fieldname=>requestedvalue with AND in between return: int The count of records returned from the specified criteria. |
| count_records_select($table, $select, array $params=null, $countitem="COUNT('x') X-Ref |
| Count the records in a table which match a particular WHERE clause. param: string $table The database table to be checked against. param: string $select A fragment of SQL to be used in a WHERE clause in the SQL call. param: array $params array of sql parameters param: string $countitem The count string to be used in the SQL call. Default is COUNT('x'). return: int The count of records returned from the specified criteria. |
| count_records_sql($sql, array $params=null) X-Ref |
| Get the result of a SQL SELECT COUNT(...) query. Given a query that counts rows, return that count. (In fact, given any query, return the first field of the first record returned. However, this method should only be used for the intended purpose.) If an error occurs, 0 is returned. param: string $sql The SQL string you wish to be executed. param: array $params array of sql parameters return: int the count |
| record_exists($table, array $conditions) X-Ref |
| Test whether a record exists in a table where all the given conditions met. param: string $table The table to check. param: array $conditions optional array $fieldname=>requestedvalue with AND in between return: bool true if a matching record exists, else false. |
| record_exists_select($table, $select, array $params=null) X-Ref |
| Test whether any records exists in a table which match a particular WHERE clause. param: string $table The database table to be checked against. param: string $select A fragment of SQL to be used in a WHERE clause in the SQL call. param: array $params array of sql parameters return: bool true if a matching record exists, else false. |
| record_exists_sql($sql, array $params=null) X-Ref |
| Test whether a SQL SELECT statement returns any records. This function returns true if the SQL statement executes without any errors and returns at least one record. param: string $sql The SQL statement to execute. param: array $params array of sql parameters return: bool true if the SQL executes without errors and returns at least one record. |
| delete_records($table, array $conditions=null) X-Ref |
| Delete the records from a table where all the given conditions met. If conditions not specified, table is truncated. param: string $table the table to delete from. param: array $conditions optional array $fieldname=>requestedvalue with AND in between return: bool true. |
| delete_records_list($table, $field, array $values) X-Ref |
| Delete the records from a table where one field match one list of values. param: string $table the table to delete from. param: string $field The field to search param: array $values array of values return: bool true. |
| delete_records_subquery(string $table, string $field, string $alias,string $subquery, array $params = []) X-Ref |
| Deletes records from a table using a subquery. The subquery should return a list of values in a single column, which match one field from the table being deleted. The $alias parameter must be set to the name of the single column in your subquery result (e.g. if the subquery is 'SELECT id FROM whatever', then it should be 'id'). This is not needed on most databases, but MySQL requires it. (On database where the subquery is inefficient, it is implemented differently.) param: string $table Table to delete from param: string $field Field in table to match param: string $alias Name of single column in subquery e.g. 'id' param: string $subquery Subquery that will return values of the field to delete param: array $params Parameters for subquery |
| sql_null_from_clause() X-Ref |
| Returns the FROM clause required by some DBs in all SELECT statements. To be used in queries not having FROM clause to provide cross_db Most DBs don't need it, hence the default is '' return: string |
| sql_bitand($int1, $int2) X-Ref |
| Returns the SQL text to be used in order to perform one bitwise AND operation between 2 integers. NOTE: The SQL result is a number and can not be used directly in SQL condition, please compare it to some number to get a bool!! param: string $int1 SQL for the first integer in the operation. param: string $int2 SQL for the second integer in the operation. return: string The piece of SQL code to be used in your statement. |
| sql_bitnot($int1) X-Ref |
| Returns the SQL text to be used in order to perform one bitwise NOT operation with 1 integer. param: int $int1 The operand integer in the operation. return: string The piece of SQL code to be used in your statement. |
| sql_bitor($int1, $int2) X-Ref |
| Returns the SQL text to be used in order to perform one bitwise OR operation between 2 integers. NOTE: The SQL result is a number and can not be used directly in SQL condition, please compare it to some number to get a bool!! param: int $int1 The first operand integer in the operation. param: int $int2 The second operand integer in the operation. return: string The piece of SQL code to be used in your statement. |
| sql_bitxor($int1, $int2) X-Ref |
| Returns the SQL text to be used in order to perform one bitwise XOR operation between 2 integers. NOTE: The SQL result is a number and can not be used directly in SQL condition, please compare it to some number to get a bool!! param: int $int1 The first operand integer in the operation. param: int $int2 The second operand integer in the operation. return: string The piece of SQL code to be used in your statement. |
| sql_modulo($int1, $int2) X-Ref |
| Returns the SQL text to be used in order to perform module '%' operation - remainder after division param: int $int1 The first operand integer in the operation. param: int $int2 The second operand integer in the operation. return: string The piece of SQL code to be used in your statement. |
| sql_ceil($fieldname) X-Ref |
| Returns the cross db correct CEIL (ceiling) expression applied to fieldname. note: Most DBs use CEIL(), hence it's the default here. param: string $fieldname The field (or expression) we are going to ceil. return: string The piece of SQL code to be used in your ceiling statement. |
| sql_cast_to_char(string $field) X-Ref |
| Return SQL for casting to char of given field/expression. Default implementation performs implicit cast using concatenation with an empty string param: string $field Table field or SQL expression to be cast return: string |
| sql_cast_char2int($fieldname, $text=false) X-Ref |
| Returns the SQL to be used in order to CAST one CHAR column to INTEGER. Be aware that the CHAR column you're trying to cast contains really int values or the RDBMS will throw an error! param: string $fieldname The name of the field to be casted. param: bool $text Specifies if the original column is one TEXT (CLOB) column (true). Defaults to false. return: string The piece of SQL code to be used in your statement. |
| sql_cast_char2real($fieldname, $text=false) X-Ref |
| Returns the SQL to be used in order to CAST one CHAR column to REAL number. Be aware that the CHAR column you're trying to cast contains really numbers or the RDBMS will throw an error! param: string $fieldname The name of the field to be casted. param: bool $text Specifies if the original column is one TEXT (CLOB) column (true). Defaults to false. return: string The piece of SQL code to be used in your statement. |
| sql_cast_2signed($fieldname) X-Ref |
| Returns the SQL to be used in order to an UNSIGNED INTEGER column to SIGNED. (Only MySQL needs this. MySQL things that 1 * -1 = 18446744073709551615 if the 1 comes from an unsigned column). param: string $fieldname The name of the field to be cast return: string The piece of SQL code to be used in your statement. |
| sql_compare_text($fieldname, $numchars=32) X-Ref |
| Returns the SQL text to be used to compare one TEXT (clob) column with one varchar column, because some RDBMS doesn't support such direct comparisons. param: string $fieldname The name of the TEXT field we need to order by param: int $numchars Number of chars to use for the ordering (defaults to 32). return: string The piece of SQL code to be used in your statement. |
| sql_equal($fieldname, $param, $casesensitive = true, $accentsensitive = true, $notequal = false) X-Ref |
| Returns an equal (=) or not equal (<>) part of a query. Note the use of this method may lead to slower queries (full scans) so use it only when needed and against already reduced data sets. param: string $fieldname Usually the name of the table column. param: string $param Usually the bound query parameter (?, :named). param: bool $casesensitive Use case sensitive search when set to true (default). param: bool $accentsensitive Use accent sensitive search when set to true (default). (not all databases support accent insensitive) param: bool $notequal True means not equal (<>) return: string The SQL code fragment. |
| sql_like($fieldname, $param, $casesensitive = true, $accentsensitive = true, $notlike = false, $escapechar = '\\') X-Ref |
| Returns 'LIKE' part of a query. param: string $fieldname Usually the name of the table column. param: string $param Usually the bound query parameter (?, :named). param: bool $casesensitive Use case sensitive search when set to true (default). param: bool $accentsensitive Use accent sensitive search when set to true (default). (not all databases support accent insensitive) param: bool $notlike True means "NOT LIKE". param: string $escapechar The escape char for '%' and '_'. return: string The SQL code fragment. |
| sql_like_escape($text, $escapechar = '\\') X-Ref |
| Escape sql LIKE special characters like '_' or '%'. param: string $text The string containing characters needing escaping. param: string $escapechar The desired escape character, defaults to '\\'. return: string The escaped sql LIKE string. |
| sql_fullname($first='firstname', $last='lastname') X-Ref |
| Returns the proper SQL (for the dbms in use) to concatenate $firstname and $lastname param: string $first User's first name (default:'firstname'). param: string $last User's last name (default:'lastname'). return: string The SQL to concatenate strings. |
| sql_order_by_text($fieldname, $numchars=32) X-Ref |
| Returns the SQL text to be used to order by one TEXT (clob) column, because some RDBMS doesn't support direct ordering of such fields. Note that the use or queries being ordered by TEXT columns must be minimised, because it's really slooooooow. param: string $fieldname The name of the TEXT field we need to order by. param: int $numchars The number of chars to use for the ordering (defaults to 32). return: string The piece of SQL code to be used in your statement. |
| sql_order_by_null(string $fieldname, int $sort = SORT_ASC) X-Ref |
| Returns the SQL text to be used to order by columns, standardising the return pattern of null values across database types to sort nulls first when ascending and last when descending. param: string $fieldname The name of the field we need to sort by. param: int $sort An order to sort the results in. return: string The piece of SQL code to be used in your statement. |
| sql_length($fieldname) X-Ref |
| Returns the SQL text to be used to calculate the length in characters of one expression. param: string $fieldname The fieldname/expression to calculate its length in characters. return: string the piece of SQL code to be used in the statement. |
| sql_substr($expr, $start, $length=false) X-Ref |
| Returns the proper substr() SQL text used to extract substrings from DB NOTE: this was originally returning only function name param: string $expr Some string field, no aggregates. param: mixed $start Integer or expression evaluating to integer (1 based value; first char has index 1) param: mixed $length Optional integer or expression evaluating to integer. return: string The sql substring extraction fragment. |
| sql_position($needle, $haystack) X-Ref |
| Returns the SQL for returning searching one string for the location of another. Note, there is no guarantee which order $needle, $haystack will be in the resulting SQL so when using this method, and both arguments contain placeholders, you should use named placeholders. param: string $needle the SQL expression that will be searched for. param: string $haystack the SQL expression that will be searched in. return: string The required searching SQL part. |
| sql_empty() X-Ref |
| This used to return empty string replacement character. return: string An empty string. |
| sql_isempty($tablename, $fieldname, $nullablefield, $textfield) X-Ref |
| Returns the proper SQL to know if one field is empty. Note that the function behavior strongly relies on the parameters passed describing the field so, please, be accurate when specifying them. Also, note that this function is not suitable to look for fields having NULL contents at all. It's all for empty values! This function should be applied in all the places where conditions of the type: ... AND fieldname = ''; are being used. Final result for text fields should be: ... AND ' . sql_isempty('tablename', 'fieldname', true/false, true); and for varchar fields result should be: ... AND fieldname = :empty; "; $params['empty'] = ''; (see parameters description below) param: string $tablename Name of the table (without prefix). Not used for now but can be param: string $fieldname Name of the field we are going to check param: bool $nullablefield For specifying if the field is nullable (true) or no (false) in the DB. param: bool $textfield For specifying if it is a text (also called clob) field (true) or a varchar one (false) return: string the sql code to be added to check for empty values |
| sql_isnotempty($tablename, $fieldname, $nullablefield, $textfield) X-Ref |
| Returns the proper SQL to know if one field is not empty. Note that the function behavior strongly relies on the parameters passed describing the field so, please, be accurate when specifying them. This function should be applied in all the places where conditions of the type: ... AND fieldname != ''; are being used. Final result for text fields should be: ... AND ' . sql_isnotempty('tablename', 'fieldname', true/false, true/false); and for varchar fields result should be: ... AND fieldname != :empty; "; $params['empty'] = ''; (see parameters description below) param: string $tablename Name of the table (without prefix). This is not used for now but can be param: string $fieldname The name of the field we are going to check. param: bool $nullablefield Specifies if the field is nullable (true) or not (false) in the DB. param: bool $textfield Specifies if it is a text (also called clob) field (true) or a varchar one (false). return: string The sql code to be added to check for non empty values. |
| sql_regex_supported() X-Ref |
| Returns true if this database driver supports regex syntax when searching. return: bool True if supported. |
| sql_regex($positivematch = true, $casesensitive = false) X-Ref |
| Returns the driver specific syntax (SQL part) for matching regex positively or negatively (inverted matching). Eg: 'REGEXP':'NOT REGEXP' or '~*' : '!~*' param: bool $positivematch param: bool $casesensitive return: string or empty if not supported |
| sql_regex_get_word_beginning_boundary_marker() X-Ref |
| Returns the word-beginning boundary marker if this database driver supports regex syntax when searching. return: string The word-beginning boundary marker. Otherwise, an empty string. |
| sql_regex_get_word_end_boundary_marker() X-Ref |
| Returns the word-end boundary marker if this database driver supports regex syntax when searching. return: string The word-end boundary marker. Otherwise, an empty string. |
| sql_intersect($selects, $fields) X-Ref |
| Returns the SQL that allows to find intersection of two or more queries param: array $selects array of SQL select queries, each of them only returns fields with the names from $fields param: string $fields comma-separated list of fields (used only by some DB engines) return: string SQL query that will return only values that are present in each of selects |
| replace_all_text_supported() X-Ref |
| Does this driver support tool_replace? return: bool |
| replace_all_text($table, database_column_info $column, $search, $replace) X-Ref |
| Replace given text in all rows of column. param: string $table name of the table param: database_column_info $column param: string $search param: string $replace |
| update_temp_table_stats() X-Ref |
| Analyze the data in temporary tables to force statistics collection after bulk data loads. return: void |
| transactions_supported() X-Ref |
| Checks and returns true if transactions are supported. It is not responsible to run productions servers on databases without transaction support ;-) Override in driver if needed. return: bool |
| is_transaction_started() X-Ref |
| Returns true if a transaction is in progress. return: bool |
| transactions_forbidden() X-Ref |
| This is a test that throws an exception if transaction in progress. This test does not force rollback of active transactions. return: void |
| start_delegated_transaction() X-Ref |
| On DBs that support it, switch to transaction mode and begin a transaction you'll need to ensure you call allow_commit() on the returned object or your changes *will* be lost. this is _very_ useful for massive updates Delegated database transactions can be nested, but only one actual database transaction is used for the outer-most delegated transaction. This method returns a transaction object which you should keep until the end of the delegated transaction. The actual database transaction will only be committed if all the nested delegated transactions commit successfully. If any part of the transaction rolls back then the whole thing is rolled back. return: moodle_transaction |
| commit_delegated_transaction(moodle_transaction $transaction) X-Ref |
| Indicates delegated transaction finished successfully. The real database transaction is committed only if all delegated transactions committed. param: moodle_transaction $transaction The transaction to commit return: void |
| rollback_delegated_transaction(moodle_transaction $transaction, $e) X-Ref |
| Call when delegated transaction failed, this rolls back all delegated transactions up to the top most level. In many cases you do not need to call this method manually, because all open delegated transactions are rolled back automatically if exceptions not caught. param: moodle_transaction $transaction An instance of a moodle_transaction. param: Exception|Throwable $e The related exception/throwable to this transaction rollback. return: void This does not return, instead the exception passed in will be rethrown. |
| force_transaction_rollback() X-Ref |
| Force rollback of all delegated transaction. Does not throw any exceptions and does not log anything. This method should be used only from default exception handlers and other core code. return: void |
| session_lock_supported() X-Ref |
| Is session lock supported in this driver? return: bool |
| get_session_lock($rowid, $timeout) X-Ref |
| Obtains the session lock. param: int $rowid The id of the row with session record. param: int $timeout The maximum allowed time to wait for the lock in seconds. return: void |
| release_session_lock($rowid) X-Ref |
| Releases the session lock. param: int $rowid The id of the row with session record. return: void |
| perf_get_reads() X-Ref |
| Returns the number of reads done by this database. return: int Number of reads. |
| want_read_slave() X-Ref |
| Returns whether we want to connect to slave database for read queries. return: bool Want read only connection |
| perf_get_reads_slave() X-Ref |
| Returns the number of reads before first write done by this database. return: int Number of reads. |
| perf_get_writes() X-Ref |
| Returns the number of writes done by this database. return: int Number of writes. |
| perf_get_queries() X-Ref |
| Returns the number of queries done by this database. return: int Number of queries. |
| perf_get_queries_time() X-Ref |
| Time waiting for the database engine to finish running all queries. return: float Number of seconds with microseconds |
| is_fulltext_search_supported() X-Ref |
| Whether the database is able to support full-text search or not. return: bool |
