Complex classes like DBSchemaManager 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 DBSchemaManager, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 9 | abstract class DBSchemaManager { |
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| 10 | |||
| 11 | /** |
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| 12 | * |
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| 13 | * @config |
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| 14 | * Check tables when running /dev/build, and repair them if necessary. |
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| 15 | * In case of large databases or more fine-grained control on how to handle |
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| 16 | * data corruption in tables, you can disable this behaviour and handle it |
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| 17 | * outside of this class, e.g. through a nightly system task with extended logging capabilities. |
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| 18 | * |
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| 19 | * @var boolean |
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| 20 | */ |
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| 21 | private static $check_and_repair_on_build = true; |
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| 22 | |||
| 23 | /** |
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| 24 | * Instance of the database controller this schema belongs to |
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| 25 | * |
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| 26 | * @var SS_Database |
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| 27 | */ |
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| 28 | protected $database = null; |
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| 29 | |||
| 30 | /** |
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| 31 | * If this is false, then information about database operations |
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| 32 | * will be displayed, eg creation of tables. |
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| 33 | * |
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| 34 | * @var boolean |
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| 35 | */ |
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| 36 | protected $supressOutput = false; |
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| 37 | |||
| 38 | /** |
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| 39 | * Injector injection point for database controller |
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| 40 | * |
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| 41 | * @param SS_Database $connector |
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| 42 | */ |
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| 43 | public function setDatabase(SS_Database $database) { |
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| 46 | |||
| 47 | /** |
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| 48 | * The table list, generated by the tableList() function. |
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| 49 | * Used by the requireTable() function. |
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| 50 | * |
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| 51 | * @var array |
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| 52 | */ |
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| 53 | protected $tableList; |
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| 54 | |||
| 55 | /** |
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| 56 | * Keeps track whether we are currently updating the schema. |
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| 57 | * |
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| 58 | * @var boolean |
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| 59 | */ |
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| 60 | protected $schemaIsUpdating = false; |
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| 61 | |||
| 62 | /** |
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| 63 | * Large array structure that represents a schema update transaction |
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| 64 | * |
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| 65 | * @var array |
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| 66 | */ |
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| 67 | protected $schemaUpdateTransaction; |
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| 68 | |||
| 69 | /** |
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| 70 | * Enable supression of database messages. |
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| 71 | */ |
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| 72 | public function quiet() { |
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| 75 | |||
| 76 | /** |
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| 77 | * Execute the given SQL query. |
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| 78 | * This abstract function must be defined by subclasses as part of the actual implementation. |
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| 79 | * It should return a subclass of SS_Query as the result. |
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| 80 | * |
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| 81 | * @param string $sql The SQL query to execute |
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| 82 | * @param int $errorLevel The level of error reporting to enable for the query |
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| 83 | * @return SS_Query |
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| 84 | */ |
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| 85 | public function query($sql, $errorLevel = E_USER_ERROR) { |
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| 88 | |||
| 89 | |||
| 90 | /** |
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| 91 | * Execute the given SQL parameterised query with the specified arguments |
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| 92 | * |
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| 93 | * @param string $sql The SQL query to execute. The ? character will denote parameters. |
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| 94 | * @param array $parameters An ordered list of arguments. |
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| 95 | * @param int $errorLevel The level of error reporting to enable for the query |
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| 96 | * @return SS_Query |
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| 97 | */ |
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| 98 | public function preparedQuery($sql, $parameters, $errorLevel = E_USER_ERROR) { |
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| 101 | |||
| 102 | /** |
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| 103 | * Initiates a schema update within a single callback |
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| 104 | * |
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| 105 | * @var callable $callback |
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| 106 | * @throws Exception |
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| 107 | */ |
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| 108 | public function schemaUpdate($callback) { |
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| 157 | |||
| 158 | /** |
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| 159 | * Cancels the schema updates requested during (but not after) schemaUpdate() call. |
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| 160 | */ |
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| 161 | public function cancelSchemaUpdate() { |
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| 165 | |||
| 166 | /** |
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| 167 | * Returns true if we are during a schema update. |
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| 168 | * |
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| 169 | * @return boolean |
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| 170 | */ |
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| 171 | function isSchemaUpdating() { |
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| 174 | |||
| 175 | /** |
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| 176 | * Returns true if schema modifications were requested during (but not after) schemaUpdate() call. |
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| 177 | * |
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| 178 | * @return boolean |
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| 179 | */ |
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| 180 | public function doesSchemaNeedUpdating() { |
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| 183 | |||
| 184 | // Transactional schema altering functions - they don't do anything except for update schemaUpdateTransaction |
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| 185 | |||
| 186 | /** |
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| 187 | * Instruct the schema manager to record a table creation to later execute |
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| 188 | * |
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| 189 | * @param string $table Name of the table |
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| 190 | * @param array $options Create table options (ENGINE, etc.) |
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| 191 | * @param array $advanced_options Advanced table creation options |
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| 192 | */ |
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| 193 | public function transCreateTable($table, $options = null, $advanced_options = null) { |
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| 202 | |||
| 203 | /** |
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| 204 | * Instruct the schema manager to record a table alteration to later execute |
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| 205 | * |
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| 206 | * @param string $table Name of the table |
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| 207 | * @param array $options Create table options (ENGINE, etc.) |
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| 208 | * @param array $advanced_options Advanced table creation options |
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| 209 | */ |
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| 210 | public function transAlterTable($table, $options, $advanced_options) { |
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| 215 | |||
| 216 | /** |
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| 217 | * Instruct the schema manager to record a field to be later created |
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| 218 | * |
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| 219 | * @param string $table Name of the table to hold this field |
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| 220 | * @param string $field Name of the field to create |
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| 221 | * @param string $schema Field specification as a string |
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| 222 | */ |
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| 223 | public function transCreateField($table, $field, $schema) { |
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| 227 | |||
| 228 | /** |
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| 229 | * Instruct the schema manager to record an index to be later created |
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| 230 | * |
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| 231 | * @param string $table Name of the table to hold this index |
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| 232 | * @param string $index Name of the index to create |
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| 233 | * @param array $schema Already parsed index specification |
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| 234 | */ |
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| 235 | public function transCreateIndex($table, $index, $schema) { |
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| 239 | |||
| 240 | /** |
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| 241 | * Instruct the schema manager to record a field to be later updated |
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| 242 | * |
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| 243 | * @param string $table Name of the table to hold this field |
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| 244 | * @param string $field Name of the field to update |
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| 245 | * @param string $schema Field specification as a string |
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| 246 | */ |
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| 247 | public function transAlterField($table, $field, $schema) { |
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| 251 | |||
| 252 | /** |
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| 253 | * Instruct the schema manager to record an index to be later updated |
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| 254 | * |
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| 255 | * @param string $table Name of the table to hold this index |
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| 256 | * @param string $index Name of the index to update |
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| 257 | * @param array $schema Already parsed index specification |
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| 258 | */ |
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| 259 | public function transAlterIndex($table, $index, $schema) { |
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| 263 | |||
| 264 | /** |
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| 265 | * Handler for the other transXXX methods - mark the given table as being altered |
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| 266 | * if it doesn't already exist |
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| 267 | * |
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| 268 | * @param string $table Name of the table to initialise |
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| 269 | */ |
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| 270 | protected function transInitTable($table) { |
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| 282 | |||
| 283 | /** |
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| 284 | * Generate the following table in the database, modifying whatever already exists |
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| 285 | * as necessary. |
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| 286 | * |
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| 287 | * @todo Change detection for CREATE TABLE $options other than "Engine" |
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| 288 | * |
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| 289 | * @param string $table The name of the table |
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| 290 | * @param array $fieldSchema A list of the fields to create, in the same form as DataObject::$db |
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| 291 | * @param array $indexSchema A list of indexes to create. See {@link requireIndex()} |
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| 292 | * The values of the array can be one of: |
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| 293 | * - true: Create a single column index on the field named the same as the index. |
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| 294 | * - array('fields' => array('A','B','C'), 'type' => 'index/unique/fulltext'): This gives you full |
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| 295 | * control over the index. |
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| 296 | * @param boolean $hasAutoIncPK A flag indicating that the primary key on this table is an autoincrement type |
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| 297 | * @param string $options SQL statement to append to the CREATE TABLE call. |
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| 298 | * @param array $extensions List of extensions |
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| 299 | */ |
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| 300 | public function requireTable($table, $fieldSchema = null, $indexSchema = null, $hasAutoIncPK = true, |
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| 361 | |||
| 362 | /** |
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| 363 | * If the given table exists, move it out of the way by renaming it to _obsolete_(tablename). |
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| 364 | * @param string $table The table name. |
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| 365 | */ |
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| 366 | public function dontRequireTable($table) { |
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| 378 | |||
| 379 | /** |
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| 380 | * Generate the given index in the database, modifying whatever already exists as necessary. |
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| 381 | * |
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| 382 | * The keys of the array are the names of the index. |
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| 383 | * The values of the array can be one of: |
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| 384 | * - true: Create a single column index on the field named the same as the index. |
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| 385 | * - array('type' => 'index|unique|fulltext', 'value' => 'FieldA, FieldB'): This gives you full |
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| 386 | * control over the index. |
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| 387 | * |
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| 388 | * @param string $table The table name. |
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| 389 | * @param string $index The index name. |
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| 390 | * @param string|array|boolean $spec The specification of the index in any |
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| 391 | * loose format. See requireTable() for more information. |
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| 392 | */ |
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| 393 | public function requireIndex($table, $index, $spec) { |
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| 427 | |||
| 428 | /** |
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| 429 | * Splits a spec string safely, considering quoted columns, whitespace, |
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| 430 | * and cleaning brackets |
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| 431 | * |
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| 432 | * @param string $spec The input index specification string |
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| 433 | * @return array List of columns in the spec |
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| 434 | */ |
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| 435 | protected function explodeColumnString($spec) { |
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| 444 | |||
| 445 | /** |
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| 446 | * Builds a properly quoted column list from an array |
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| 447 | * |
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| 448 | * @param array $columns List of columns to implode |
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| 449 | * @return string A properly quoted list of column names |
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| 450 | */ |
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| 451 | protected function implodeColumnList($columns) { |
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| 455 | |||
| 456 | /** |
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| 457 | * Given an index specification in the form of a string ensure that each |
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| 458 | * column name is property quoted, stripping brackets and modifiers. |
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| 459 | * This index may also be in the form of a "CREATE INDEX..." sql fragment |
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| 460 | * |
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| 461 | * @param string $spec The input specification or query. E.g. 'unique (Column1, Column2)' |
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| 462 | * @return string The properly quoted column list. E.g. '"Column1", "Column2"' |
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| 463 | */ |
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| 464 | protected function quoteColumnSpecString($spec) { |
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| 468 | |||
| 469 | /** |
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| 470 | * Given an index spec determines the index type |
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| 471 | * |
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| 472 | * @param array|string $spec |
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| 473 | * @return string |
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| 474 | */ |
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| 475 | protected function determineIndexType($spec) { |
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| 485 | |||
| 486 | /** |
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| 487 | * Converts an array or string index spec into a universally useful array |
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| 488 | * |
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| 489 | * @see convertIndexSpec() for approximate inverse |
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| 490 | * @param string|array $spec |
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| 491 | * @return array The resulting spec array with the required fields name, type, and value |
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| 492 | */ |
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| 493 | protected function parseIndexSpec($name, $spec) { |
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| 517 | |||
| 518 | /** |
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| 519 | * This takes the index spec which has been provided by a class (ie static $indexes = blah blah) |
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| 520 | * and turns it into a proper string. |
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| 521 | * Some indexes may be arrays, such as fulltext and unique indexes, and this allows database-specific |
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| 522 | * arrays to be created. See {@link requireTable()} for details on the index format. |
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| 523 | * |
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| 524 | * @see http://dev.mysql.com/doc/refman/5.0/en/create-index.html |
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| 525 | * @see parseIndexSpec() for approximate inverse |
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| 526 | * |
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| 527 | * @param string|array $indexSpec |
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| 528 | */ |
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| 529 | protected function convertIndexSpec($indexSpec) { |
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| 536 | |||
| 537 | /** |
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| 538 | * Returns true if the given table is exists in the current database |
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| 539 | * |
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| 540 | * @param string $table Name of table to check |
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| 541 | * @return boolean Flag indicating existence of table |
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| 542 | */ |
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| 543 | abstract public function hasTable($tableName); |
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| 544 | |||
| 545 | /** |
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| 546 | * Return true if the table exists and already has a the field specified |
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| 547 | * |
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| 548 | * @param string $tableName - The table to check |
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| 549 | * @param string $fieldName - The field to check |
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| 550 | * @return bool - True if the table exists and the field exists on the table |
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| 551 | */ |
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| 552 | public function hasField($tableName, $fieldName) { |
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| 557 | |||
| 558 | /** |
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| 559 | * Generate the given field on the table, modifying whatever already exists as necessary. |
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| 560 | * |
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| 561 | * @param string $table The table name. |
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| 562 | * @param string $field The field name. |
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| 563 | * @param array|string $spec The field specification. If passed in array syntax, the specific database |
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| 564 | * driver takes care of the ALTER TABLE syntax. If passed as a string, its assumed to |
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| 565 | * be prepared as a direct SQL framgment ready for insertion into ALTER TABLE. In this case you'll |
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| 566 | * need to take care of database abstraction in your DBField subclass. |
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| 567 | */ |
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| 568 | public function requireField($table, $field, $spec) { |
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| 666 | |||
| 667 | /** |
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| 668 | * If the given field exists, move it out of the way by renaming it to _obsolete_(fieldname). |
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| 669 | * |
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| 670 | * @param string $table |
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| 671 | * @param string $fieldName |
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| 672 | */ |
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| 673 | public function dontRequireField($table, $fieldName) { |
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| 689 | |||
| 690 | /** |
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| 691 | * Show a message about database alteration |
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| 692 | * |
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| 693 | * @param string $message to display |
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| 694 | * @param string $type one of [created|changed|repaired|obsolete|deleted|error] |
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| 695 | */ |
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| 696 | public function alterationMessage($message, $type = "") { |
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| 750 | |||
| 751 | /** |
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| 752 | * This returns the data type for the id column which is the primary key for each table |
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| 753 | * |
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| 754 | * @param boolean $asDbValue |
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| 755 | * @param boolean $hasAutoIncPK |
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| 756 | * @return string |
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| 757 | */ |
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| 758 | abstract public function IdColumn($asDbValue = false, $hasAutoIncPK = true); |
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| 759 | |||
| 760 | /** |
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| 761 | * Checks a table's integrity and repairs it if necessary. |
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| 762 | * |
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| 763 | * @param string $tableName The name of the table. |
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| 764 | * @return boolean Return true if the table has integrity after the method is complete. |
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| 765 | */ |
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| 766 | abstract public function checkAndRepairTable($tableName); |
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| 767 | |||
| 768 | /** |
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| 769 | * Returns the values of the given enum field |
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| 770 | * |
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| 771 | * @param string $tableName Name of table to check |
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| 772 | * @param string $fieldName name of enum field to check |
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| 773 | * @return array List of enum values |
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| 774 | */ |
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| 775 | abstract public function enumValuesForField($tableName, $fieldName); |
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| 776 | |||
| 777 | |||
| 778 | /* |
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| 779 | * This is a lookup table for data types. |
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| 780 | * For instance, Postgres uses 'INT', while MySQL uses 'UNSIGNED' |
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| 781 | * So this is a DB-specific list of equivilents. |
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| 782 | * |
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| 783 | * @param string $type |
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| 784 | * @return string |
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| 785 | */ |
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| 786 | abstract public function dbDataType($type); |
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| 787 | |||
| 788 | /** |
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| 789 | * Retrieves the list of all databases the user has access to |
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| 790 | * |
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| 791 | * @return array List of database names |
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| 792 | */ |
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| 793 | abstract public function databaseList(); |
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| 794 | |||
| 795 | /** |
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| 796 | * Determine if the database with the specified name exists |
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| 797 | * |
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| 798 | * @param string $name Name of the database to check for |
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| 799 | * @return boolean Flag indicating whether this database exists |
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| 800 | */ |
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| 801 | abstract public function databaseExists($name); |
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| 802 | |||
| 803 | /** |
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| 804 | * Create a database with the specified name |
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| 805 | * |
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| 806 | * @param string $name Name of the database to create |
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| 807 | * @return boolean True if successful |
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| 808 | */ |
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| 809 | abstract public function createDatabase($name); |
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| 810 | |||
| 811 | /** |
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| 812 | * Drops a database with the specified name |
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| 813 | * |
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| 814 | * @param string $name Name of the database to drop |
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| 815 | */ |
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| 816 | abstract public function dropDatabase($name); |
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| 817 | |||
| 818 | /** |
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| 819 | * Alter an index on a table. |
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| 820 | * |
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| 821 | * @param string $tableName The name of the table. |
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| 822 | * @param string $indexName The name of the index. |
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| 823 | * @param string $indexSpec The specification of the index, see {@link SS_Database::requireIndex()} |
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| 824 | * for more details. |
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| 825 | * @todo Find out where this is called from - Is it even used? Aren't indexes always dropped and re-added? |
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| 826 | */ |
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| 827 | abstract public function alterIndex($tableName, $indexName, $indexSpec); |
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| 828 | |||
| 829 | /** |
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| 830 | * Determines the key that should be used to identify this index |
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| 831 | * when retrieved from DBSchemaManager->indexList. |
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| 832 | * In some connectors this is the database-visible name, in others the |
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| 833 | * usercode-visible name. |
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| 834 | * |
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| 835 | * @param string $table |
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| 836 | * @param string $index |
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| 837 | * @param array $spec |
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| 838 | * @return string Key for this index |
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| 839 | */ |
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| 840 | abstract protected function indexKey($table, $index, $spec); |
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| 841 | |||
| 842 | /** |
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| 843 | * Return the list of indexes in a table. |
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| 844 | * |
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| 845 | * @param string $table The table name. |
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| 846 | * @return array[array] List of current indexes in the table, each in standard |
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| 847 | * array form. The key for this array should be predictable using the indexKey |
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| 848 | * method |
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| 849 | */ |
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| 850 | abstract public function indexList($table); |
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| 851 | |||
| 852 | /** |
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| 853 | * Returns a list of all tables in the database. |
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| 854 | * Keys are table names in lower case, values are table names in case that |
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| 855 | * database expects. |
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| 856 | * |
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| 857 | * @return array |
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| 858 | */ |
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| 859 | abstract public function tableList(); |
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| 860 | |||
| 861 | /** |
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| 862 | * Create a new table. |
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| 863 | * |
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| 864 | * @param string $table The name of the table |
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| 865 | * @param array $fields A map of field names to field types |
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| 866 | * @param array $indexes A map of indexes |
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| 867 | * @param array $options An map of additional options. The available keys are as follows: |
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| 868 | * - 'MSSQLDatabase'/'MySQLDatabase'/'PostgreSQLDatabase' - database-specific options such as "engine" for MySQL. |
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| 869 | * - 'temporary' - If true, then a temporary table will be created |
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| 870 | * @param $advancedOptions Advanced creation options |
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| 871 | * @return string The table name generated. This may be different from the table name, for example with temporary |
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| 872 | * tables. |
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| 873 | */ |
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| 874 | abstract public function createTable($table, $fields = null, $indexes = null, $options = null, |
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| 876 | |||
| 877 | /** |
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| 878 | * Alter a table's schema. |
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| 879 | * |
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| 880 | * @param string $table The name of the table to alter |
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| 881 | * @param array $newFields New fields, a map of field name => field schema |
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| 882 | * @param array $newIndexes New indexes, a map of index name => index type |
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| 883 | * @param array $alteredFields Updated fields, a map of field name => field schema |
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| 884 | * @param array $alteredIndexes Updated indexes, a map of index name => index type |
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| 885 | * @param array $alteredOptions |
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| 886 | * @param array $advancedOptions |
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| 887 | */ |
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| 888 | abstract public function alterTable($table, $newFields = null, $newIndexes = null, $alteredFields = null, |
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| 890 | |||
| 891 | /** |
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| 892 | * Rename a table. |
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| 893 | * |
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| 894 | * @param string $oldTableName The old table name. |
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| 895 | * @param string $newTableName The new table name. |
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| 896 | */ |
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| 897 | abstract public function renameTable($oldTableName, $newTableName); |
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| 898 | |||
| 899 | /** |
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| 900 | * Create a new field on a table. |
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| 901 | * |
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| 902 | * @param string $table Name of the table. |
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| 903 | * @param string $field Name of the field to add. |
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| 904 | * @param string $spec The field specification, eg 'INTEGER NOT NULL' |
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| 905 | */ |
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| 906 | abstract public function createField($table, $field, $spec); |
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| 907 | |||
| 908 | /** |
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| 909 | * Change the database column name of the given field. |
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| 910 | * |
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| 911 | * @param string $tableName The name of the tbale the field is in. |
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| 912 | * @param string $oldName The name of the field to change. |
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| 913 | * @param string $newName The new name of the field |
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| 914 | */ |
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| 915 | abstract public function renameField($tableName, $oldName, $newName); |
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| 916 | |||
| 917 | /** |
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| 918 | * Get a list of all the fields for the given table. |
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| 919 | * Returns a map of field name => field spec. |
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| 920 | * |
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| 921 | * @param string $table The table name. |
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| 922 | * @return array |
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| 923 | */ |
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| 924 | abstract public function fieldList($table); |
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| 925 | |||
| 926 | /** |
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| 927 | * |
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| 928 | * This allows the cached values for a table's field list to be erased. |
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| 929 | * If $tablename is empty, then the whole cache is erased. |
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| 930 | * |
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| 931 | * @param string $tableName |
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| 932 | * |
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| 933 | * @return boolean |
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| 934 | */ |
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| 935 | public function clearCachedFieldlist($tableName = false) { |
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| 938 | |||
| 939 | } |
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| 940 |
This check looks for PHPDoc comments describing methods or function parameters that do not exist on the corresponding method or function.
Consider the following example. The parameter
$italyis not defined by the methodfinale(...).The most likely cause is that the parameter was removed, but the annotation was not.