Complex classes like DB often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use DB, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
||
| 9 | class DB { |
||
| 10 | |||
| 11 | /** |
||
| 12 | * This constant was added in SilverStripe 2.4 to indicate that SQL-queries |
||
| 13 | * should now use ANSI-compatible syntax. The most notable affect of this |
||
| 14 | * change is that table and field names should be escaped with double quotes |
||
| 15 | * and not backticks |
||
| 16 | */ |
||
| 17 | const USE_ANSI_SQL = true; |
||
| 18 | |||
| 19 | |||
| 20 | /** |
||
| 21 | * The global database connection. |
||
| 22 | * @var SS_Database |
||
| 23 | */ |
||
| 24 | private static $connections = array(); |
||
| 25 | |||
| 26 | /** |
||
| 27 | * The last SQL query run. |
||
| 28 | * @var string |
||
| 29 | */ |
||
| 30 | public static $lastQuery; |
||
| 31 | |||
| 32 | /** |
||
| 33 | * Internal flag to keep track of when db connection was attempted. |
||
| 34 | */ |
||
| 35 | private static $connection_attempted = false; |
||
| 36 | |||
| 37 | /** |
||
| 38 | * Set the global database connection. |
||
| 39 | * Pass an object that's a subclass of SS_Database. This object will be used when {@link DB::query()} |
||
| 40 | * is called. |
||
| 41 | * |
||
| 42 | * @param $connection The connecton object to set as the connection. |
||
| 43 | * @param $name The name to give to this connection. If you omit this argument, the connection |
||
| 44 | * will be the default one used by the ORM. However, you can store other named connections to |
||
| 45 | * be accessed through DB::get_conn($name). This is useful when you have an application that |
||
| 46 | * needs to connect to more than one database. |
||
| 47 | */ |
||
| 48 | public static function set_conn(SS_Database $connection, $name = 'default') { |
||
| 51 | |||
| 52 | /** |
||
| 53 | * @deprecated since version 4.0 Use DB::set_conn instead |
||
| 54 | */ |
||
| 55 | public static function setConn(SS_Database $connection, $name = 'default') { |
||
| 59 | |||
| 60 | /** |
||
| 61 | * Get the global database connection. |
||
| 62 | * |
||
| 63 | * @param string $name An optional name given to a connection in the DB::setConn() call. If omitted, |
||
| 64 | * the default connection is returned. |
||
| 65 | * @return SS_Database |
||
| 66 | */ |
||
| 67 | public static function get_conn($name = 'default') { |
||
| 72 | |||
| 73 | /** |
||
| 74 | * @deprecated since version 4.0 Use DB::get_conn instead |
||
| 75 | */ |
||
| 76 | public static function getConn($name = 'default') { |
||
| 80 | |||
| 81 | /** |
||
| 82 | * Retrieves the schema manager for the current database |
||
| 83 | * |
||
| 84 | * @param string $name An optional name given to a connection in the DB::setConn() call. If omitted, |
||
| 85 | * the default connection is returned. |
||
| 86 | * @return DBSchemaManager |
||
| 87 | */ |
||
| 88 | public static function get_schema($name = 'default') { |
||
| 92 | |||
| 93 | /** |
||
| 94 | * Builds a sql query with the specified connection |
||
| 95 | * |
||
| 96 | * @param SQLExpression $expression The expression object to build from |
||
| 97 | * @param array $parameters Out parameter for the resulting query parameters |
||
| 98 | * @param string $name An optional name given to a connection in the DB::setConn() call. If omitted, |
||
| 99 | * the default connection is returned. |
||
| 100 | * @return string The resulting SQL as a string |
||
| 101 | */ |
||
| 102 | public static function build_sql(SQLExpression $expression, &$parameters, $name = 'default') { |
||
| 111 | |||
| 112 | /** |
||
| 113 | * Retrieves the connector object for the current database |
||
| 114 | * |
||
| 115 | * @param string $name An optional name given to a connection in the DB::setConn() call. If omitted, |
||
| 116 | * the default connection is returned. |
||
| 117 | * @return DBConnector |
||
| 118 | */ |
||
| 119 | public static function get_connector($name = 'default') { |
||
| 123 | |||
| 124 | /** |
||
| 125 | * Set an alternative database in a browser cookie, |
||
| 126 | * with the cookie lifetime set to the browser session. |
||
| 127 | * This is useful for integration testing on temporary databases. |
||
| 128 | * |
||
| 129 | * There is a strict naming convention for temporary databases to avoid abuse: |
||
| 130 | * <prefix> (default: 'ss_') + tmpdb + <7 digits> |
||
| 131 | * As an additional security measure, temporary databases will |
||
| 132 | * be ignored in "live" mode. |
||
| 133 | * |
||
| 134 | * Note that the database will be set on the next request. |
||
| 135 | * Set it to null to revert to the main database. |
||
| 136 | */ |
||
| 137 | public static function set_alternative_database_name($name = null) { |
||
| 173 | |||
| 174 | /** |
||
| 175 | * Get the name of the database in use |
||
| 176 | */ |
||
| 177 | public static function get_alternative_database_name() { |
||
| 198 | |||
| 199 | /** |
||
| 200 | * Determines if the name is valid, as a security |
||
| 201 | * measure against setting arbitrary databases. |
||
| 202 | * |
||
| 203 | * @param String $name |
||
| 204 | * @return Boolean |
||
| 205 | */ |
||
| 206 | public static function valid_alternative_database_name($name) { |
||
| 213 | |||
| 214 | /** |
||
| 215 | * Connect to a database. |
||
| 216 | * |
||
| 217 | * Given the database configuration, this method will create the correct |
||
| 218 | * subclass of {@link SS_Database}. |
||
| 219 | * |
||
| 220 | * @param array $database A map of options. The 'type' is the name of the subclass of SS_Database to use. For the |
||
| 221 | * rest of the options, see the specific class. |
||
| 222 | * @param string $name identifier for the connection |
||
| 223 | * |
||
| 224 | * @return SS_Database |
||
| 225 | */ |
||
| 226 | public static function connect($databaseConfig, $label = 'default') { |
||
| 250 | |||
| 251 | /** |
||
| 252 | * Returns true if a database connection has been attempted. |
||
| 253 | * In particular, it lets the caller know if we're still so early in the execution pipeline that |
||
| 254 | * we haven't even tried to connect to the database yet. |
||
| 255 | */ |
||
| 256 | public static function connection_attempted() { |
||
| 259 | |||
| 260 | /** |
||
| 261 | * @deprecated since version 4.0 DB::getConnect was never implemented and is obsolete |
||
| 262 | */ |
||
| 263 | public static function getConnect($parameters) { |
||
| 266 | |||
| 267 | /** |
||
| 268 | * Execute the given SQL query. |
||
| 269 | * @param string $sql The SQL query to execute |
||
| 270 | * @param int $errorLevel The level of error reporting to enable for the query |
||
| 271 | * @return SS_Query |
||
| 272 | */ |
||
| 273 | public static function query($sql, $errorLevel = E_USER_ERROR) { |
||
| 278 | |||
| 279 | /** |
||
| 280 | * Helper function for generating a list of parameter placeholders for the |
||
| 281 | * given argument(s) |
||
| 282 | * |
||
| 283 | * @param array|integer $input An array of items needing placeholders, or a |
||
| 284 | * number to specify the number of placeholders |
||
| 285 | * @param string $join The string to join each placeholder together with |
||
| 286 | * @return string|null Either a list of placeholders, or null |
||
| 287 | */ |
||
| 288 | public static function placeholders($input, $join = ', ') { |
||
| 299 | |||
| 300 | /** |
||
| 301 | * @param string $sql The parameterised query |
||
| 302 | * @param array $parameters The parameters to inject into the query |
||
| 303 | * |
||
| 304 | * @return string |
||
| 305 | */ |
||
| 306 | public static function inline_parameters($sql, $parameters) { |
||
| 353 | |||
| 354 | /** |
||
| 355 | * Execute the given SQL parameterised query with the specified arguments |
||
| 356 | * |
||
| 357 | * @param string $sql The SQL query to execute. The ? character will denote parameters. |
||
| 358 | * @param array $parameters An ordered list of arguments. |
||
| 359 | * @param int $errorLevel The level of error reporting to enable for the query |
||
| 360 | * @return SS_Query |
||
| 361 | */ |
||
| 362 | public static function prepared_query($sql, $parameters, $errorLevel = E_USER_ERROR) { |
||
| 367 | |||
| 368 | /** |
||
| 369 | * Execute a complex manipulation on the database. |
||
| 370 | * A manipulation is an array of insert / or update sequences. The keys of the array are table names, |
||
| 371 | * and the values are map containing 'command' and 'fields'. Command should be 'insert' or 'update', |
||
| 372 | * and fields should be a map of field names to field values, including quotes. The field value can |
||
| 373 | * also be a SQL function or similar. |
||
| 374 | * |
||
| 375 | * Example: |
||
| 376 | * <code> |
||
| 377 | * array( |
||
| 378 | * // Command: insert |
||
| 379 | * "table name" => array( |
||
| 380 | * "command" => "insert", |
||
| 381 | * "fields" => array( |
||
| 382 | * "ClassName" => "'MyClass'", // if you're setting a literal, you need to escape and provide quotes |
||
| 383 | * "Created" => "now()", // alternatively, you can call DB functions |
||
| 384 | * "ID" => 234, |
||
| 385 | * ), |
||
| 386 | * "id" => 234 // an alternative to providing ID in the fields list |
||
| 387 | * ), |
||
| 388 | * |
||
| 389 | * // Command: update |
||
| 390 | * "other table" => array( |
||
| 391 | * "command" => "update", |
||
| 392 | * "fields" => array( |
||
| 393 | * "ClassName" => "'MyClass'", |
||
| 394 | * "LastEdited" => "now()", |
||
| 395 | * ), |
||
| 396 | * "where" => "ID = 234", |
||
| 397 | * "id" => 234 // an alternative to providing a where clause |
||
| 398 | * ), |
||
| 399 | * ) |
||
| 400 | * </code> |
||
| 401 | * |
||
| 402 | * You'll note that only one command on a given table can be called. |
||
| 403 | * That's a limitation of the system that's due to it being written for {@link DataObject::write()}, |
||
| 404 | * which needs to do a single write on a number of different tables. |
||
| 405 | * |
||
| 406 | * @todo Update this to support paramaterised queries |
||
| 407 | * |
||
| 408 | * @param array $manipulation |
||
| 409 | */ |
||
| 410 | public static function manipulate($manipulation) { |
||
| 414 | |||
| 415 | /** |
||
| 416 | * Get the autogenerated ID from the previous INSERT query. |
||
| 417 | * @return int |
||
| 418 | */ |
||
| 419 | public static function get_generated_id($table) { |
||
| 422 | |||
| 423 | /** |
||
| 424 | * @deprecated since version 4.0 Use DB::get_generated_id instead |
||
| 425 | */ |
||
| 426 | public static function getGeneratedID($table) { |
||
| 430 | |||
| 431 | /** |
||
| 432 | * Check if the connection to the database is active. |
||
| 433 | * |
||
| 434 | * @return boolean |
||
| 435 | */ |
||
| 436 | public static function is_active() { |
||
| 439 | |||
| 440 | /** |
||
| 441 | * @deprecated since version 4.0 Use DB::is_active instead |
||
| 442 | */ |
||
| 443 | public static function isActive() { |
||
| 447 | |||
| 448 | /** |
||
| 449 | * Create the database and connect to it. This can be called if the |
||
| 450 | * initial database connection is not successful because the database |
||
| 451 | * does not exist. |
||
| 452 | * |
||
| 453 | * @param string $database Name of database to create |
||
| 454 | * @return boolean Returns true if successful |
||
| 455 | */ |
||
| 456 | public static function create_database($database) { |
||
| 459 | |||
| 460 | /** |
||
| 461 | * @deprecated since version 4.0 Use DB::create_database instead |
||
| 462 | */ |
||
| 463 | public static function createDatabase($connect, $username, $password, $database) { |
||
| 467 | |||
| 468 | /** |
||
| 469 | * Create a new table. |
||
| 470 | * @param string $tableName The name of the table |
||
| 471 | * @param array$fields A map of field names to field types |
||
| 472 | * @param array $indexes A map of indexes |
||
| 473 | * @param array $options An map of additional options. The available keys are as follows: |
||
| 474 | * - 'MSSQLDatabase'/'MySQLDatabase'/'PostgreSQLDatabase' - database-specific options such as "engine" |
||
| 475 | * for MySQL. |
||
| 476 | * - 'temporary' - If true, then a temporary table will be created |
||
| 477 | * @return string The table name generated. This may be different from the table name, for example with |
||
| 478 | * temporary tables. |
||
| 479 | */ |
||
| 480 | public static function create_table($table, $fields = null, $indexes = null, $options = null, |
||
| 485 | |||
| 486 | /** |
||
| 487 | * @deprecated since version 4.0 Use DB::create_table instead |
||
| 488 | */ |
||
| 489 | public static function createTable($table, $fields = null, $indexes = null, $options = null) { |
||
| 493 | |||
| 494 | /** |
||
| 495 | * Create a new field on a table. |
||
| 496 | * @param string $table Name of the table. |
||
| 497 | * @param string $field Name of the field to add. |
||
| 498 | * @param string $spec The field specification, eg 'INTEGER NOT NULL' |
||
| 499 | */ |
||
| 500 | public static function create_field($table, $field, $spec) { |
||
| 503 | |||
| 504 | /** |
||
| 505 | * @deprecated since version 4.0 Use DB::create_field instead |
||
| 506 | */ |
||
| 507 | public static function createField($table, $field, $spec) { |
||
| 511 | |||
| 512 | /** |
||
| 513 | * Generate the following table in the database, modifying whatever already exists |
||
| 514 | * as necessary. |
||
| 515 | * |
||
| 516 | * @param string $table The name of the table |
||
| 517 | * @param string $fieldSchema A list of the fields to create, in the same form as DataObject::$db |
||
| 518 | * @param string $indexSchema A list of indexes to create. The keys of the array are the names of the index. |
||
| 519 | * The values of the array can be one of: |
||
| 520 | * - true: Create a single column index on the field named the same as the index. |
||
| 521 | * - array('fields' => array('A','B','C'), 'type' => 'index/unique/fulltext'): This gives you full |
||
| 522 | * control over the index. |
||
| 523 | * @param boolean $hasAutoIncPK A flag indicating that the primary key on this table is an autoincrement type |
||
| 524 | * @param string $options SQL statement to append to the CREATE TABLE call. |
||
| 525 | * @param array $extensions List of extensions |
||
| 526 | */ |
||
| 527 | public static function require_table($table, $fieldSchema = null, $indexSchema = null, $hasAutoIncPK = true, |
||
| 533 | |||
| 534 | /** |
||
| 535 | * @deprecated since version 4.0 Use DB::require_table instead |
||
| 536 | */ |
||
| 537 | public static function requireTable($table, $fieldSchema = null, $indexSchema = null, $hasAutoIncPK = true, |
||
| 543 | |||
| 544 | /** |
||
| 545 | * Generate the given field on the table, modifying whatever already exists as necessary. |
||
| 546 | * |
||
| 547 | * @param string $table The table name. |
||
| 548 | * @param string $field The field name. |
||
| 549 | * @param string $spec The field specification. |
||
| 550 | */ |
||
| 551 | public static function require_field($table, $field, $spec) { |
||
| 554 | |||
| 555 | /** |
||
| 556 | * @deprecated since version 4.0 Use DB::require_field instead |
||
| 557 | */ |
||
| 558 | public static function requireField($table, $field, $spec) { |
||
| 562 | |||
| 563 | /** |
||
| 564 | * Generate the given index in the database, modifying whatever already exists as necessary. |
||
| 565 | * |
||
| 566 | * @param string $table The table name. |
||
| 567 | * @param string $index The index name. |
||
| 568 | * @param string|boolean $spec The specification of the index. See requireTable() for more information. |
||
| 569 | */ |
||
| 570 | public static function require_index($table, $index, $spec) { |
||
| 573 | |||
| 574 | /** |
||
| 575 | * @deprecated since version 4.0 Use DB::require_index instead |
||
| 576 | */ |
||
| 577 | public static function requireIndex($table, $index, $spec) { |
||
| 581 | |||
| 582 | /** |
||
| 583 | * If the given table exists, move it out of the way by renaming it to _obsolete_(tablename). |
||
| 584 | * |
||
| 585 | * @param string $table The table name. |
||
| 586 | */ |
||
| 587 | public static function dont_require_table($table) { |
||
| 590 | |||
| 591 | /** |
||
| 592 | * @deprecated since version 4.0 Use DB::dont_require_table instead |
||
| 593 | */ |
||
| 594 | public static function dontRequireTable($table) { |
||
| 598 | |||
| 599 | /** |
||
| 600 | * See {@link SS_Database->dontRequireField()}. |
||
| 601 | * |
||
| 602 | * @param string $table The table name. |
||
| 603 | * @param string $fieldName The field name not to require |
||
| 604 | */ |
||
| 605 | public static function dont_require_field($table, $fieldName) { |
||
| 608 | |||
| 609 | /** |
||
| 610 | * @deprecated since version 4.0 Use DB::dont_require_field instead |
||
| 611 | */ |
||
| 612 | public static function dontRequireField($table, $fieldName) { |
||
| 616 | |||
| 617 | /** |
||
| 618 | * Checks a table's integrity and repairs it if necessary. |
||
| 619 | * |
||
| 620 | * @param string $tableName The name of the table. |
||
| 621 | * @return boolean Return true if the table has integrity after the method is complete. |
||
| 622 | */ |
||
| 623 | public static function check_and_repair_table($table) { |
||
| 626 | |||
| 627 | /** |
||
| 628 | * @deprecated since version 4.0 Use DB::check_and_repair_table instead |
||
| 629 | */ |
||
| 630 | public static function checkAndRepairTable($table) { |
||
| 634 | |||
| 635 | /** |
||
| 636 | * Return the number of rows affected by the previous operation. |
||
| 637 | * |
||
| 638 | * @return integer The number of affected rows |
||
| 639 | */ |
||
| 640 | public static function affected_rows() { |
||
| 643 | |||
| 644 | /** |
||
| 645 | * @deprecated since version 4.0 Use DB::affected_rows instead |
||
| 646 | */ |
||
| 647 | public static function affectedRows() { |
||
| 651 | |||
| 652 | /** |
||
| 653 | * Returns a list of all tables in the database. |
||
| 654 | * The table names will be in lower case. |
||
| 655 | * |
||
| 656 | * @return array The list of tables |
||
| 657 | */ |
||
| 658 | public static function table_list() { |
||
| 661 | |||
| 662 | /** |
||
| 663 | * @deprecated since version 4.0 Use DB::table_list instead |
||
| 664 | */ |
||
| 665 | public static function tableList() { |
||
| 669 | |||
| 670 | /** |
||
| 671 | * Get a list of all the fields for the given table. |
||
| 672 | * Returns a map of field name => field spec. |
||
| 673 | * |
||
| 674 | * @param string $table The table name. |
||
| 675 | * @return array The list of fields |
||
| 676 | */ |
||
| 677 | public static function field_list($table) { |
||
| 680 | |||
| 681 | /** |
||
| 682 | * @deprecated since version 4.0 Use DB::field_list instead |
||
| 683 | */ |
||
| 684 | public static function fieldList($table) { |
||
| 688 | |||
| 689 | /** |
||
| 690 | * Enable supression of database messages. |
||
| 691 | */ |
||
| 692 | public static function quiet() { |
||
| 695 | |||
| 696 | /** |
||
| 697 | * Show a message about database alteration |
||
| 698 | * |
||
| 699 | * @param string $message to display |
||
| 700 | * @param string $type one of [created|changed|repaired|obsolete|deleted|error] |
||
| 701 | */ |
||
| 702 | public static function alteration_message($message, $type = "") { |
||
| 705 | |||
| 706 | } |
||
| 707 |
In PHP, under loose comparison (like
==, or!=, orswitchconditions), values of different types might be equal.For
stringvalues, the empty string''is a special case, in particular the following results might be unexpected: