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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| 13 | class DB implements DBInterface |
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| 14 | { |
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| 15 | /** |
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| 16 | * @var DriverInterface |
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| 17 | */ |
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| 18 | protected $driver; |
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| 19 | /** |
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| 20 | * @var Table[] |
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| 21 | */ |
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| 22 | protected $tables = []; |
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| 23 | |||
| 24 | /** |
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| 25 | * Create an instance. |
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| 26 | * |
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| 27 | * @param DriverInterface|string $driver a driver instance or a connection string |
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| 28 | */ |
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| 29 | 3 | public function __construct($driver) { |
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| 32 | /** |
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| 33 | * Create a driver instance from a connection string |
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| 34 | * @param string $connectionString the connection string |
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| 35 | * @return DriverInterface |
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| 36 | */ |
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| 37 | 3 | public static function getDriver(string $connectionString) |
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| 82 | /** |
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| 83 | * Prepare a statement. |
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| 84 | * Use only if you need a single query to be performed multiple times with different parameters. |
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| 85 | * |
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| 86 | * @param string $sql the query to prepare - use `?` for arguments |
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| 87 | * @return StatementInterface the prepared statement |
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| 88 | */ |
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| 89 | 1 | public function prepare(string $sql) : StatementInterface |
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| 118 | /** |
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| 119 | * Run a query (prepare & execute). |
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| 120 | * @param string $sql SQL query |
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| 121 | * @param array|null $par parameters (optional) |
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| 122 | * @return ResultInterface the result of the execution |
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| 123 | */ |
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| 124 | 27 | public function query(string $sql, $par = null) : ResultInterface |
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| 132 | /** |
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| 133 | * Run a SELECT query and get an array-like result. |
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| 134 | * When using `get` the data is kept in the database client and fetched as needed (not in PHP memory as with `all`) |
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| 135 | * |
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| 136 | * @param string $sql SQL query |
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| 137 | * @param array $par parameters |
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| 138 | * @param string $key column name to use as the array index |
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| 139 | * @param bool $skip do not include the column used as index in the value (defaults to `false`) |
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| 140 | * @param bool $opti if a single column is returned - do not use an array wrapper (defaults to `true`) |
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| 141 | * |
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| 142 | * @return Collection the result of the execution |
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| 143 | */ |
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| 144 | 21 | public function get(string $sql, $par = null, string $key = null, bool $skip = false, bool $opti = true): Collection |
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| 167 | /** |
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| 168 | * Run a SELECT query and get a single row |
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| 169 | * @param string $sql SQL query |
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| 170 | * @param array $par parameters |
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| 171 | * @param bool $opti if a single column is returned - do not use an array wrapper (defaults to `true`) |
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| 172 | * @return Collection the result of the execution |
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| 173 | */ |
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| 174 | 7 | public function one(string $sql, $par = null, bool $opti = true) |
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| 178 | /** |
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| 179 | * Run a SELECT query and get an array |
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| 180 | * @param string $sql SQL query |
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| 181 | * @param array $par parameters |
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| 182 | * @param string $key column name to use as the array index |
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| 183 | * @param bool $skip do not include the column used as index in the value (defaults to `false`) |
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| 184 | * @param bool $opti if a single column is returned - do not use an array wrapper (defaults to `true`) |
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| 185 | * @return Collection the result of the execution |
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| 186 | */ |
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| 187 | 2 | public function all(string $sql, $par = null, string $key = null, bool $skip = false, bool $opti = true) : array |
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| 191 | /** |
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| 192 | * Begin a transaction. |
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| 193 | * @return $this |
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| 194 | */ |
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| 195 | 1 | public function begin() : DBInterface |
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| 202 | /** |
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| 203 | * Commit a transaction. |
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| 204 | * @return $this |
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| 205 | */ |
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| 206 | 1 | public function commit() : DBInterface |
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| 213 | /** |
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| 214 | * Rollback a transaction. |
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| 215 | * @return $this |
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| 216 | */ |
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| 217 | 1 | public function rollback() : DBInterface |
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| 224 | /** |
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| 225 | * Get the current driver name (`"mysql"`, `"postgre"`, etc). |
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| 226 | * @return string the current driver name |
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| 227 | */ |
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| 228 | 2 | public function driver() : string |
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| 232 | |||
| 233 | 13 | public function definition(string $table, bool $detectRelations = true) : Table |
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| 239 | /** |
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| 240 | * Parse all tables from the database. |
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| 241 | * @return $this |
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| 242 | */ |
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| 243 | public function parseSchema() |
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| 248 | /** |
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| 249 | * Get the full schema as an array that you can serialize and store |
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| 250 | * @return array |
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| 251 | */ |
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| 252 | 1 | public function getSchema($asPlainArray = true) |
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| 280 | /** |
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| 281 | * Load the schema data from a schema definition array (obtained from getSchema) |
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| 282 | * @param array $data the schema definition |
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| 283 | * @return $this |
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| 284 | */ |
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| 285 | public function setSchema(array $data) |
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| 314 | |||
| 315 | /** |
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| 316 | * Initialize a table query |
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| 317 | * @param string $table the table to query |
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| 318 | * @return TableQuery |
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| 319 | */ |
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| 320 | 13 | public function table($table) |
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| 328 | } |