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 |
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| 15 | abstract class Db { |
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| 16 | use Utils\FetchModeTrait; |
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| 17 | |||
| 18 | const QUERY_DEFINE = 'define'; |
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| 19 | const QUERY_READ = 'read'; |
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| 20 | const QUERY_WRITE = 'write'; |
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| 21 | |||
| 22 | const INDEX_PK = 'primary'; |
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| 23 | const INDEX_IX = 'index'; |
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| 24 | const INDEX_UNIQUE = 'unique'; |
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| 25 | |||
| 26 | const OPTION_REPLACE = 'replace'; |
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| 27 | const OPTION_IGNORE = 'ignore'; |
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| 28 | const OPTION_UPSERT = 'upsert'; |
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| 29 | const OPTION_TRUNCATE = 'truncate'; |
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| 30 | const OPTION_DROP = 'drop'; |
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| 31 | const OPTION_FETCH_MODE = 'fetchMode'; |
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| 32 | |||
| 33 | const OP_EQ = '='; |
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| 34 | const OP_GT = '>'; |
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| 35 | const OP_GTE = '>='; |
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| 36 | const OP_IN = '$in'; |
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| 37 | const OP_LIKE = '$like'; |
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| 38 | const OP_LT = '<'; |
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| 39 | const OP_LTE = '<='; |
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| 40 | const OP_NEQ = '<>'; |
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| 41 | |||
| 42 | const OP_AND = '$and'; |
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| 43 | const OP_OR = '$or'; |
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| 44 | |||
| 45 | /** |
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| 46 | * @var string[] Maps PDO drivers to db classes. |
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| 47 | */ |
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| 48 | private static $drivers = [ |
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| 49 | 'mysql' => MySqlDb::class, |
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| 50 | 'sqlite' => SqliteDb::class |
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| 51 | ]; |
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| 52 | |||
| 53 | /** |
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| 54 | * @var array The canonical database types. |
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| 55 | */ |
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| 56 | private static $types = [ |
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| 57 | // String |
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| 58 | 'char' => ['type' => 'string', 'length' => true], |
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| 59 | 'varchar' => ['type' => 'string', 'length' => true], |
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| 60 | 'tinytext' => ['type' => 'string', 'schema' => ['maxLength' => 255]], |
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| 61 | 'text' => ['type' => 'string', 'schema' => ['maxLength' => 65535]], |
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| 62 | 'mediumtext' => ['type' => 'string', 'schema' => ['maxLength' => 16777215]], |
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| 63 | 'longtext' => ['type' => 'string', 'schema' => ['maxLength' => 4294967295]], |
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| 64 | 'binary' => ['type' => 'string', 'length' => true], |
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| 65 | 'varbinary' => ['type' => 'string', 'length' => true], |
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| 66 | |||
| 67 | // Boolean |
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| 68 | 'bool' => ['type' => 'boolean'], |
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| 69 | |||
| 70 | // Integer |
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| 71 | 'byte' => ['type' => 'integer', 'schema' => ['maximum' => 127, 'minimum' => -128]], |
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| 72 | 'short' => ['type' => 'integer', 'schema' => ['maximum' => 32767, 'minimum' => -32768]], |
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| 73 | 'int' => ['type' => 'integer', 'schema' => ['maximum' => 2147483647, 'minimum' => -2147483648]], |
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| 74 | 'long' => ['type' => 'integer'], |
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| 75 | |||
| 76 | // Number |
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| 77 | 'float' => ['type' => 'number'], |
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| 78 | 'double' => ['type' => 'number'], |
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| 79 | 'decimal' => ['type' => 'number', 'precision' => true], |
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| 80 | 'numeric' => ['type' => 'number', 'precision' => true], |
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| 81 | |||
| 82 | // Date/Time |
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| 83 | 'datetime' => ['type' => 'datetime'], |
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| 84 | 'timestamp' => ['type' => 'datetime'], |
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| 85 | |||
| 86 | // Enum |
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| 87 | 'enum' => ['type' => 'string', 'enum' => true], |
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| 88 | |||
| 89 | // Schema types |
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| 90 | 'string' => 'varchar', |
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| 91 | 'boolean' => 'bool', |
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| 92 | 'integer' => 'int', |
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| 93 | 'number' => 'float', |
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| 94 | |||
| 95 | // Other aliases |
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| 96 | 'character' => 'char', |
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| 97 | 'tinyint' => 'byte', |
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| 98 | 'int8' => 'byte', |
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| 99 | 'smallint' => 'short', |
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| 100 | 'int16' => 'short', |
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| 101 | 'int32' => 'int', |
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| 102 | 'bigint' => 'long', |
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| 103 | 'int64' => 'long', |
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| 104 | 'real' => 'double' |
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| 105 | ]; |
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| 106 | |||
| 107 | /** |
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| 108 | * @var string The database prefix. |
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| 109 | */ |
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| 110 | private $px = ''; |
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| 111 | |||
| 112 | /** |
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| 113 | * @var array A cached copy of the table schemas indexed by lowercase name. |
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| 114 | */ |
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| 115 | private $tables = []; |
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| 116 | |||
| 117 | /** |
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| 118 | * @var array|null A cached copy of the table names indexed by lowercase name. |
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| 119 | */ |
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| 120 | private $tableNames = null; |
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| 121 | |||
| 122 | /** |
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| 123 | * @var \PDO |
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| 124 | */ |
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| 125 | private $pdo; |
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| 126 | |||
| 127 | /** |
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| 128 | * Initialize an instance of the {@link MySqlDb} class. |
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| 129 | * |
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| 130 | * @param PDO $pdo The connection to the database. |
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| 131 | * @param string $px The database prefix. |
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| 132 | */ |
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| 133 | public function __construct(PDO $pdo, $px = '') { |
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| 140 | |||
| 141 | /** |
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| 142 | * Get the name of the class that handles a database driver. |
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| 143 | * |
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| 144 | * @param string|PDO $driver The name of the driver or a database connection. |
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| 145 | * @return null|string Returns the driver classname or **null** if one isn't found. |
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| 146 | */ |
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| 147 | public static function driverClass($driver) { |
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| 157 | |||
| 158 | /** |
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| 159 | * Add a table to the database. |
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| 160 | * |
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| 161 | * @param array $tableDef The table definition. |
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| 162 | * @param array $options An array of additional options when adding the table. |
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| 163 | */ |
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| 164 | abstract protected function createTableDb(array $tableDef, array $options = []); |
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| 165 | |||
| 166 | /** |
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| 167 | * Alter a table in the database. |
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| 168 | * |
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| 169 | * When altering a table you pass an array with three optional keys: add, drop, and alter. |
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| 170 | * Each value is consists of a table definition in a format that would be passed to {@link Db::setTableDef()}. |
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| 171 | * |
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| 172 | * @param array $alterDef The alter definition. |
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| 173 | * @param array $options An array of additional options when adding the table. |
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| 174 | */ |
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| 175 | abstract protected function alterTableDb(array $alterDef, array $options = []); |
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| 176 | |||
| 177 | /** |
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| 178 | * Drop a table. |
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| 179 | * |
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| 180 | * @param string $table The name of the table to drop. |
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| 181 | * @param array $options An array of additional options when adding the table. |
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| 182 | */ |
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| 183 | 6 | final public function dropTable($table, array $options = []) { |
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| 190 | |||
| 191 | /** |
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| 192 | * Perform the actual table drop. |
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| 193 | * |
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| 194 | * @param string $table The name of the table to drop. |
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| 195 | * @param array $options An array of additional options when adding the table. |
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| 196 | */ |
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| 197 | abstract protected function dropTableDb($table, array $options = []); |
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| 198 | |||
| 199 | /** |
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| 200 | * Get the names of all the tables in the database. |
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| 201 | * |
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| 202 | * @return string[] Returns an array of table names without prefixes. |
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| 203 | */ |
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| 204 | final public function fetchTableNames() { |
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| 219 | |||
| 220 | /** |
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| 221 | * Fetch the table names from the underlying database layer. |
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| 222 | * |
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| 223 | * The driver should return all table names. It doesn't have to strip the prefix. |
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| 224 | * |
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| 225 | * @return string[] |
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| 226 | */ |
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| 227 | abstract protected function fetchTableNamesDb(); |
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| 228 | |||
| 229 | /** |
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| 230 | * Get a table definition. |
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| 231 | * |
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| 232 | * @param string $table The name of the table. |
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| 233 | * @return array|null Returns the table definition or null if the table does not exist. |
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| 234 | */ |
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| 235 | 64 | final public function fetchTableDef($table) { |
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| 257 | |||
| 258 | /** |
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| 259 | * Fetch the table definition from the database. |
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| 260 | * |
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| 261 | * @param string $table The name of the table to get. |
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| 262 | * @return array|null Returns the table def or **null** if the table doesn't exist. |
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| 263 | */ |
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| 264 | abstract protected function fetchTableDefDb($table); |
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| 265 | |||
| 266 | |||
| 267 | /** |
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| 268 | * Get the column definitions for a table. |
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| 269 | * |
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| 270 | * @param string $table The name of the table to get the columns for. |
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| 271 | * @return array|null Returns an array of column definitions. |
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| 272 | */ |
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| 273 | 1 | final public function fetchColumnDefs($table) { |
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| 288 | |||
| 289 | /** |
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| 290 | * Get the column definitions from the database. |
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| 291 | * |
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| 292 | * @param string $table The name of the table to fetch the columns for. |
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| 293 | * @return array|null |
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| 294 | */ |
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| 295 | abstract protected function fetchColumnDefsDb($table); |
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| 296 | |||
| 297 | /** |
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| 298 | * Get the canonical type based on a type string. |
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| 299 | * |
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| 300 | * @param string $type A type string. |
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| 301 | * @return array|null Returns the type schema array or **null** if a type isn't found. |
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| 302 | */ |
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| 303 | 49 | public static function typeDef($type) { |
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| 376 | |||
| 377 | /** |
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| 378 | * Get the database type string from a type definition. |
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| 379 | * |
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| 380 | * This is the opposite of {@link Db::typeDef()}. |
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| 381 | * |
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| 382 | * @param array $typeDef The type definition array. |
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| 383 | * @return string Returns a db type string. |
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| 384 | */ |
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| 385 | 28 | protected static function dbType(array $typeDef) { |
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| 406 | |||
| 407 | |||
| 408 | /** |
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| 409 | * Get the native database type based on a type schema. |
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| 410 | * |
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| 411 | * The default implementation of this method returns the canonical db types. Individual database classes will have |
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| 412 | * to override to provide any differences. |
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| 413 | * |
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| 414 | * @param array $type The type schema. |
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| 415 | * @return string |
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| 416 | */ |
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| 417 | abstract protected function nativeDbType(array $type); |
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| 418 | |||
| 419 | /** |
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| 420 | * Set a table definition to the database. |
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| 421 | * |
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| 422 | * @param array $tableDef The table definition. |
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| 423 | * @param array $options An array of additional options when adding the table. |
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| 424 | */ |
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| 425 | 64 | final public function defineTable(array $tableDef, array $options = []) { |
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| 498 | |||
| 499 | /** |
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| 500 | * Find the primary key in an array of indexes. |
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| 501 | * |
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| 502 | * @param array $indexes The indexes to search. |
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| 503 | * @return array|null Returns the primary key or **null** if there isn't one. |
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| 504 | */ |
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| 505 | 51 | protected function findPrimaryKeyIndex(array $indexes) { |
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| 513 | |||
| 514 | /** |
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| 515 | * Move the primary key index into the correct place for database drivers. |
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| 516 | * |
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| 517 | * @param string $tableName The name of the table. |
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| 518 | * @param array &$tableDef The table definition. |
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| 519 | * @param array|null $curTableDef The current database table def used to resolve conflicts in some names. |
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| 520 | * @throws \Exception Throws an exception when there is a mismatch between the primary index and the primary key |
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| 521 | * defined on the columns themselves. |
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| 522 | */ |
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| 523 | 64 | private function fixIndexes($tableName, array &$tableDef, $curTableDef = null) { |
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| 568 | |||
| 569 | /** |
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| 570 | * Get the database prefix. |
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| 571 | * |
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| 572 | * @return string Returns the current db prefix. |
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| 573 | */ |
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| 574 | public function getPx() { |
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| 577 | |||
| 578 | /** |
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| 579 | * Set the database prefix. |
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| 580 | * |
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| 581 | * @param string $px The new database prefix. |
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| 582 | */ |
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| 583 | public function setPx($px) { |
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| 586 | |||
| 587 | /** |
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| 588 | * Compare two index definitions to see if they have the same columns and same type. |
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| 589 | * |
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| 590 | * @param array $a The first index. |
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| 591 | * @param array $b The second index. |
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| 592 | * @return int Returns an integer less than, equal to, or greater than zero if {@link $a} is |
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| 593 | * considered to be respectively less than, equal to, or greater than {@link $b}. |
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| 594 | */ |
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| 595 | 45 | private function indexCompare(array $a, array $b) { |
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| 607 | |||
| 608 | /** |
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| 609 | * Get data from the database. |
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| 610 | * |
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| 611 | * @param string|Identifier $table The name of the table to get the data from. |
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| 612 | * @param array $where An array of where conditions. |
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| 613 | * @param array $options An array of additional options. |
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| 614 | * @return \PDOStatement Returns the result set. |
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| 615 | */ |
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| 616 | abstract public function get($table, array $where, array $options = []); |
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| 617 | |||
| 618 | /** |
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| 619 | * Get a single row from the database. |
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| 620 | * |
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| 621 | * This is a convenience method that calls {@link Db::get()} and shifts off the first row. |
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| 622 | * |
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| 623 | * @param string|Identifier $table The name of the table to get the data from. |
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| 624 | * @param array $where An array of where conditions. |
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| 625 | * @param array $options An array of additional options. |
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| 626 | * @return array|object|null Returns the row or false if there is no row. |
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| 627 | */ |
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| 628 | 14 | final public function getOne($table, array $where, array $options = []) { |
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| 635 | |||
| 636 | /** |
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| 637 | * Insert a row into a table. |
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| 638 | * |
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| 639 | * @param string $table The name of the table to insert into. |
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| 640 | * @param array $row The row of data to insert. |
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| 641 | * @param array $options An array of options for the insert. |
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| 642 | * |
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| 643 | * Db::OPTION_IGNORE |
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| 644 | * : Whether or not to ignore inserts that lead to a duplicate key. *default false* |
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| 645 | * Db::OPTION_REPLACE |
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| 646 | * : Whether or not to replace duplicate keys. *default false* |
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| 647 | * Db::OPTION_UPSERT |
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| 648 | * : Whether or not to update the existing data when duplicate keys exist. |
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| 649 | * |
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| 650 | * @return mixed Returns the id of the inserted record, **true** if the table doesn't have an auto increment, or **false** otherwise. |
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| 651 | * @see Db::load() |
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| 652 | */ |
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| 653 | abstract public function insert($table, array $row, array $options = []); |
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| 654 | |||
| 655 | /** |
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| 656 | * Load many rows into a table. |
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| 657 | * |
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| 658 | * @param string $table The name of the table to insert into. |
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| 659 | * @param \Traversable|array $rows A dataset to insert. |
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| 660 | * Note that all rows must contain the same columns. |
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| 661 | * The first row will be looked at for the structure of the insert and the rest of the rows will use this structure. |
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| 662 | * @param array $options An array of options for the inserts. See {@link Db::insert()} for details. |
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| 663 | * @see Db::insert() |
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| 664 | */ |
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| 665 | public function load($table, $rows, array $options = []) { |
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| 670 | |||
| 671 | |||
| 672 | /** |
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| 673 | * Update a row or rows in a table. |
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| 674 | * |
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| 675 | * @param string $table The name of the table to update. |
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| 676 | * @param array $set The values to set. |
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| 677 | * @param array $where The where filter for the update. |
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| 678 | * @param array $options An array of options for the update. |
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| 679 | * @return int Returns the number of affected rows. |
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| 680 | */ |
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| 681 | abstract public function update($table, array $set, array $where, array $options = []); |
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| 682 | |||
| 683 | /** |
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| 684 | * Delete rows from a table. |
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| 685 | * |
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| 686 | * @param string $table The name of the table to delete from. |
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| 687 | * @param array $where The where filter of the delete. |
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| 688 | * @param array $options An array of options. |
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| 689 | * |
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| 690 | * Db:OPTION_TRUNCATE |
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| 691 | * : Truncate the table instead of deleting rows. In this case {@link $where} must be blank. |
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| 692 | * @return int Returns the number of affected rows. |
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| 693 | */ |
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| 694 | abstract public function delete($table, array $where, array $options = []); |
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| 695 | |||
| 696 | /** |
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| 697 | * Reset the internal table definition cache. |
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| 698 | * |
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| 699 | * @return $this |
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| 700 | */ |
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| 701 | 8 | public function reset() { |
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| 706 | |||
| 707 | /** |
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| 708 | * Build a standardized index name from an index definition. |
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| 709 | * |
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| 710 | * @param string $tableName The name of the table the index is in. |
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| 711 | * @param array $indexDef The index definition. |
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| 712 | * @return string Returns the index name. |
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| 713 | */ |
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| 714 | 64 | protected function buildIndexName($tableName, array $indexDef) { |
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| 727 | |||
| 728 | /** |
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| 729 | * Execute a query that fetches data. |
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| 730 | * |
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| 731 | * @param string $sql The query to execute. |
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| 732 | * @param array $params Input parameters for the query. |
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| 733 | * @param array $options Additional options. |
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| 734 | * @return \PDOStatement Returns the result of the query. |
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| 735 | * @throws \PDOException Throws an exception if something went wrong during the query. |
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| 736 | */ |
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| 737 | 85 | protected function query($sql, array $params = [], array $options = []) { |
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| 759 | |||
| 760 | /** |
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| 761 | * Query the database and return a row count. |
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| 762 | * |
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| 763 | * @param string $sql The query to execute. |
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| 764 | * @param array $params Input parameters for the query. |
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| 765 | * @param array $options Additional options. |
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| 766 | * @return int |
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| 767 | */ |
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| 768 | 38 | protected function queryModify($sql, array $params = [], array $options = []) { |
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| 773 | |||
| 774 | /** |
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| 775 | * Query the database and return the ID of the record that was inserted. |
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| 776 | * |
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| 777 | * @param string $sql The query to execute. |
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| 778 | * @param array $params Input parameters for the query. |
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| 779 | * @param array $options Additional options. |
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| 780 | * @return int Returns the record ID. |
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| 781 | */ |
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| 782 | 17 | protected function queryID($sql, array $params = [], array $options = []) { |
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| 788 | |||
| 789 | /** |
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| 790 | * Query the database for a database define. |
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| 791 | * |
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| 792 | * @param string $sql The query to execute. |
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| 793 | * @param array $options Additional options. |
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| 794 | */ |
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| 795 | 28 | protected function queryDefine($sql, array $options = []) { |
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| 799 | |||
| 800 | /** |
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| 801 | * Safely get a value out of an array. |
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| 802 | * |
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| 803 | * This function will always return a value even if the array key doesn't exist. |
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| 804 | * The self::val() function is one of the biggest workhorses of Vanilla and shows up a lot throughout other code. |
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| 805 | * It's much preferable to use this function if your not sure whether or not an array key exists rather than |
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| 806 | * using @ error suppression. |
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| 807 | * |
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| 808 | * This function uses optimizations found in the [facebook libphputil library](https://github.com/facebook/libphutil). |
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| 809 | * |
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| 810 | * @param string|int $key The array key. |
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| 811 | * @param array|object $array The array to get the value from. |
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| 812 | * @param mixed $default The default value to return if the key doesn't exist. |
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| 813 | * @return mixed The item from the array or `$default` if the array key doesn't exist. |
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| 814 | * @category Array Functions |
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| 815 | */ |
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| 816 | 82 | protected static function val($key, $array, $default = null) { |
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| 839 | |||
| 840 | /** |
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| 841 | * Escape an identifier. |
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| 842 | * |
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| 843 | * @param string|Literal $identifier The identifier to escape. |
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| 844 | * @return string Returns the field properly escaped. |
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| 845 | */ |
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| 846 | 89 | public function escape($identifier) { |
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| 852 | |||
| 853 | /** |
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| 854 | * Escape a a like string so that none of its characters work as wildcards. |
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| 855 | * |
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| 856 | * @param string $str The string to escape. |
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| 857 | * @return string Returns an escaped string. |
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| 858 | */ |
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| 859 | protected function escapeLike($str) { |
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| 862 | |||
| 863 | /** |
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| 864 | * Prefix a table name. |
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| 865 | * |
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| 866 | * @param string|Identifier $table The name of the table to prefix. |
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| 867 | * @param bool $escape Whether or not to escape the output. |
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| 868 | * @return string Returns a full table name. |
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| 869 | */ |
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| 870 | 89 | protected function prefixTable($table, $escape = true) { |
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| 878 | |||
| 879 | /** |
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| 880 | * Strip the database prefix off a table name. |
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| 881 | * |
||
| 882 | * @param string $table The name of the table to strip. |
||
| 883 | * @return string Returns the table name stripped of the prefix. |
||
| 884 | */ |
||
| 885 | protected function stripPrefix($table) { |
||
| 892 | |||
| 893 | /** |
||
| 894 | * Optionally quote a where value. |
||
| 895 | * |
||
| 896 | * @param mixed $value The value to quote. |
||
| 897 | * @param string $column The column being operated on. It must already be quoted. |
||
| 898 | * @return string Returns the value, optionally quoted. |
||
| 899 | * @internal param bool $quote Whether or not to quote the value. |
||
| 900 | */ |
||
| 901 | 41 | public function quote($value, $column = '') { |
|
| 909 | |||
| 910 | /** |
||
| 911 | * Gets the {@link PDO} object for this connection. |
||
| 912 | * |
||
| 913 | * @return \PDO |
||
| 914 | */ |
||
| 915 | 89 | public function getPDO() { |
|
| 918 | |||
| 919 | /** |
||
| 920 | * Set the connection to the database. |
||
| 921 | * |
||
| 922 | * @param PDO $pdo The new connection to the database. |
||
| 923 | * @return $this |
||
| 924 | */ |
||
| 925 | public function setPDO(PDO $pdo) { |
||
| 929 | } |
||
| 930 |
This check looks for multiple assignments in successive lines of code. It will report an issue if the operators are not in a straight line.
To visualize
will produce issues in the first and second line, while this second example
will produce no issues.