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<?php |
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|
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/** |
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* SQLite database configurator. |
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* |
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* This class initializes and configures the SQLite database, so that it can be |
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* used by the SQLite driver to translate and emulate MySQL queries in SQLite. |
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* |
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* The configurator ensures that tables required for emulating MySQL behaviors |
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* are created and populated with necessary data. It is also able to partially |
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* repair and update these tables and metadata in case of database corruption. |
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* |
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* @access private |
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*/ |
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class WP_SQLite_Configurator { |
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/** |
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* The SQLite driver instance. |
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* |
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* @var WP_MySQL_On_SQLite |
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*/ |
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private $driver; |
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|
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/** |
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* A service for managing MySQL INFORMATION_SCHEMA tables in SQLite. |
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* |
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* @var WP_SQLite_Information_Schema_Builder |
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*/ |
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private $schema_builder; |
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|
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/** |
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* A service for reconstructing the MySQL INFORMATION_SCHEMA tables in SQLite. |
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* |
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* @var WP_SQLite_Information_Schema_Reconstructor |
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*/ |
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private $schema_reconstructor; |
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|
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/** |
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* Constructor. |
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* |
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* @param WP_MySQL_On_SQLite $driver The SQLite driver instance. |
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* @param WP_SQLite_Information_Schema_Builder $schema_builder The information schema builder instance. |
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*/ |
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public function __construct( |
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WP_MySQL_On_SQLite $driver, |
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WP_SQLite_Information_Schema_Builder $schema_builder |
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) { |
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$this->driver = $driver; |
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$this->schema_builder = $schema_builder; |
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$this->schema_reconstructor = new WP_SQLite_Information_Schema_Reconstructor( |
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$driver, |
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$schema_builder |
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); |
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} |
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|
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/** |
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* Ensure that the SQLite database is configured. |
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* |
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* This method checks if the database is configured for the latest SQLite |
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* driver version, and if it is not, it will configure the database. |
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*/ |
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public function ensure_database_configured(): void { |
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$version = SQLITE_DRIVER_VERSION; |
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$db_version = $this->driver->get_saved_driver_version(); |
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if ( version_compare( $version, $db_version ) > 0 ) { |
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$this->configure_database(); |
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} |
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} |
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|
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/** |
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* Configure the SQLite database. |
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* |
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* This method creates tables used for emulating MySQL behaviors in SQLite, |
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* and populates them with necessary data. When it is used with an already |
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* configured database, it will update the configuration as per the current |
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* SQLite driver version and attempt to repair any configuration corruption. |
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*/ |
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public function configure_database(): void { |
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// Use an EXCLUSIVE transaction to prevent multiple connections |
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// from attempting to configure the database at the same time. |
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$this->driver->execute_sqlite_query( 'BEGIN EXCLUSIVE TRANSACTION' ); |
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try { |
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$this->ensure_global_variables_table(); |
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$this->schema_builder->ensure_information_schema_tables(); |
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$this->schema_reconstructor->ensure_correct_information_schema(); |
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$this->save_current_driver_version(); |
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$this->ensure_database_data(); |
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} catch ( Throwable $e ) { |
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$this->driver->execute_sqlite_query( 'ROLLBACK' ); |
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throw $e; |
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} |
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$this->driver->execute_sqlite_query( 'COMMIT' ); |
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} |
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|
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/** |
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* Ensure that the global variables table exists. |
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* |
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* This method configures a database table to store MySQL global variables |
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* and other internal configuration values. |
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*/ |
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private function ensure_global_variables_table(): void { |
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$this->driver->execute_sqlite_query( |
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sprintf( |
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'CREATE TABLE IF NOT EXISTS %s (name TEXT PRIMARY KEY, value TEXT)', |
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$this->driver->get_connection()->quote_identifier( |
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WP_MySQL_On_SQLite::GLOBAL_VARIABLES_TABLE_NAME |
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) |
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) |
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); |
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} |
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|
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/** |
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* Ensure that the database data is correctly populated. |
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* |
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* This method ensures that the "INFORMATION_SCHEMA.SCHEMATA" table contains |
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* records for both the "INFORMATION_SCHEMA" database and the user database. |
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* At the moment, only a single user database is supported. |
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* |
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* Additionally, this method ensures that the user database name is stored |
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* correctly in all the information schema tables. |
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*/ |
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public function ensure_database_data(): void { |
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// Get all databases from the "SCHEMATA" table. |
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$schemata_table = $this->schema_builder->get_table_name( false, 'schemata' ); |
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$databases = $this->driver->execute_sqlite_query( |
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sprintf( |
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'SELECT SCHEMA_NAME FROM %s', |
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$this->driver->get_connection()->quote_identifier( $schemata_table ) |
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) |
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)->fetchAll( PDO::FETCH_COLUMN ); // phpcs:disable WordPress.DB.RestrictedClasses.mysql__PDO |
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|
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// Ensure that the "INFORMATION_SCHEMA" database record exists. |
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if ( ! in_array( 'information_schema', $databases, true ) ) { |
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$this->driver->execute_sqlite_query( |
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sprintf( |
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'INSERT INTO %s (SCHEMA_NAME, DEFAULT_CHARACTER_SET_NAME, DEFAULT_COLLATION_NAME) VALUES (?, ?, ?)', |
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$this->driver->get_connection()->quote_identifier( $schemata_table ) |
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), |
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// The "INFORMATION_SCHEMA" database stays on "utf8mb3" even in MySQL 8 and 9. |
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array( 'information_schema', 'utf8mb3', 'utf8mb3_general_ci' ) |
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); |
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} |
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|
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// Get the existing user database name. |
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$existing_user_db_name = null; |
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foreach ( $databases as $database ) { |
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if ( 'information_schema' !== strtolower( $database ) ) { |
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$existing_user_db_name = $database; |
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break; |
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} |
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} |
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|
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// Ensure that the user database record exists. |
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if ( null === $existing_user_db_name ) { |
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$existing_user_db_name = WP_SQLite_Information_Schema_Builder::SAVED_DATABASE_NAME; |
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$this->driver->execute_sqlite_query( |
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sprintf( |
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'INSERT INTO %s (SCHEMA_NAME, DEFAULT_CHARACTER_SET_NAME, DEFAULT_COLLATION_NAME) VALUES (?, ?, ?)', |
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$this->driver->get_connection()->quote_identifier( $schemata_table ) |
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), |
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// @TODO: This should probably be version-dependent. |
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// Before MySQL 8, the default was different. |
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array( $existing_user_db_name, 'utf8mb4', 'utf8mb4_0900_ai_ci' ) |
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); |
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} |
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|
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// Migrate from older versions without dynamic database names. |
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$saved_database_name = WP_SQLite_Information_Schema_Builder::SAVED_DATABASE_NAME; |
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if ( $saved_database_name !== $existing_user_db_name ) { |
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// INFORMATION_SCHEMA.SCHEMATA |
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$this->driver->execute_sqlite_query( |
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sprintf( |
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"UPDATE %s SET SCHEMA_NAME = ? WHERE SCHEMA_NAME != 'information_schema'", |
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$this->driver->get_connection()->quote_identifier( $schemata_table ) |
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), |
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array( $saved_database_name ) |
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); |
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|
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// INFORMATION_SCHEMA.TABLES |
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$tables_table = $this->schema_builder->get_table_name( false, 'tables' ); |
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$this->driver->execute_sqlite_query( |
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sprintf( |
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"UPDATE %s SET TABLE_SCHEMA = ? WHERE TABLE_SCHEMA != 'information_schema'", |
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$this->driver->get_connection()->quote_identifier( $tables_table ) |
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), |
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array( $saved_database_name ) |
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); |
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|
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// INFORMATION_SCHEMA.COLUMNS |
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$columns_table = $this->schema_builder->get_table_name( false, 'columns' ); |
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$this->driver->execute_sqlite_query( |
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sprintf( |
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"UPDATE %s SET TABLE_SCHEMA = ? WHERE TABLE_SCHEMA != 'information_schema'", |
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$this->driver->get_connection()->quote_identifier( $columns_table ) |
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), |
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array( $saved_database_name ) |
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); |
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|
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// INFORMATION_SCHEMA.STATISTICS |
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$statistics_table = $this->schema_builder->get_table_name( false, 'statistics' ); |
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$this->driver->execute_sqlite_query( |
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sprintf( |
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"UPDATE %s SET TABLE_SCHEMA = ?, INDEX_SCHEMA = ? WHERE TABLE_SCHEMA != 'information_schema'", |
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$this->driver->get_connection()->quote_identifier( $statistics_table ) |
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), |
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array( $saved_database_name, $saved_database_name ) |
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); |
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|
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// INFORMATION_SCHEMA.TABLE_CONSTRAINTS |
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$table_constraints_table = $this->schema_builder->get_table_name( false, 'table_constraints' ); |
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$this->driver->execute_sqlite_query( |
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sprintf( |
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"UPDATE %s SET TABLE_SCHEMA = ?, CONSTRAINT_SCHEMA = ? WHERE TABLE_SCHEMA != 'information_schema'", |
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$this->driver->get_connection()->quote_identifier( $table_constraints_table ) |
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), |
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array( $saved_database_name, $saved_database_name ) |
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); |
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|
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// INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS |
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$referential_constraints_table = $this->schema_builder->get_table_name( false, 'referential_constraints' ); |
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$this->driver->execute_sqlite_query( |
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sprintf( |
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"UPDATE %s SET CONSTRAINT_SCHEMA = ?, UNIQUE_CONSTRAINT_SCHEMA = ? WHERE CONSTRAINT_SCHEMA != 'information_schema'", |
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$this->driver->get_connection()->quote_identifier( $referential_constraints_table ) |
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), |
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array( $saved_database_name, $saved_database_name ) |
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); |
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|
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// INFORMATION_SCHEMA.KEY_COLUMN_USAGE |
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$key_column_usage_table = $this->schema_builder->get_table_name( false, 'key_column_usage' ); |
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$this->driver->execute_sqlite_query( |
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sprintf( |
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"UPDATE %s |
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SET |
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TABLE_SCHEMA = ?, |
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CONSTRAINT_SCHEMA = ?, |
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REFERENCED_TABLE_SCHEMA = CASE WHEN REFERENCED_TABLE_SCHEMA IS NULL THEN NULL ELSE ? END |
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WHERE TABLE_SCHEMA != 'information_schema'", |
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$this->driver->get_connection()->quote_identifier( $key_column_usage_table ) |
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), |
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array( $saved_database_name, $saved_database_name, $saved_database_name ) |
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); |
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|
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// INFORMATION_SCHEMA.CHECK_CONSTRAINTS |
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$check_constraints_table = $this->schema_builder->get_table_name( false, 'check_constraints' ); |
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$this->driver->execute_sqlite_query( |
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sprintf( |
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"UPDATE %s SET CONSTRAINT_SCHEMA = ? WHERE CONSTRAINT_SCHEMA != 'information_schema'", |
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$this->driver->get_connection()->quote_identifier( $check_constraints_table ) |
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), |
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array( $saved_database_name ) |
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); |
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} |
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} |
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|
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/** |
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* Save the current SQLite driver version. |
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* |
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* This method saves the current SQLite driver version to the database. |
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*/ |
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private function save_current_driver_version(): void { |
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$this->driver->execute_sqlite_query( |
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sprintf( |
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'INSERT INTO %s (name, value) VALUES (?, ?) ON CONFLICT(name) DO UPDATE SET value = ?', |
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$this->driver->get_connection()->quote_identifier( |
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WP_MySQL_On_SQLite::GLOBAL_VARIABLES_TABLE_NAME |
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) |
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), |
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array( |
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WP_MySQL_On_SQLite::DRIVER_VERSION_VARIABLE_NAME, |
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SQLITE_DRIVER_VERSION, |
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SQLITE_DRIVER_VERSION, |
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) |
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); |
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} |
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} |
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|
