Complex classes like QueryBuilder 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 QueryBuilder, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 20 | class QueryBuilder extends \yii\db\QueryBuilder |
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| 21 | { |
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| 22 | /** |
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| 23 | * @var array mapping from abstract column types (keys) to physical column types (values). |
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| 24 | */ |
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| 25 | public $typeMap = [ |
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| 26 | Schema::TYPE_PK => 'int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY', |
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| 27 | Schema::TYPE_UPK => 'int(10) UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY', |
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| 28 | Schema::TYPE_BIGPK => 'bigint(20) NOT NULL AUTO_INCREMENT PRIMARY KEY', |
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| 29 | Schema::TYPE_UBIGPK => 'bigint(20) UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY', |
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| 30 | Schema::TYPE_CHAR => 'char(1)', |
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| 31 | Schema::TYPE_STRING => 'varchar(255)', |
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| 32 | Schema::TYPE_TEXT => 'text', |
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| 33 | Schema::TYPE_SMALLINT => 'smallint(6)', |
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| 34 | Schema::TYPE_INTEGER => 'int(11)', |
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| 35 | Schema::TYPE_BIGINT => 'bigint(20)', |
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| 36 | Schema::TYPE_FLOAT => 'float', |
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| 37 | Schema::TYPE_DOUBLE => 'double', |
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| 38 | Schema::TYPE_DECIMAL => 'decimal(10,0)', |
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| 39 | Schema::TYPE_DATETIME => 'datetime', |
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| 40 | Schema::TYPE_TIMESTAMP => 'timestamp', |
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| 41 | Schema::TYPE_TIME => 'time', |
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| 42 | Schema::TYPE_DATE => 'date', |
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| 43 | Schema::TYPE_BINARY => 'blob', |
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| 44 | Schema::TYPE_BOOLEAN => 'tinyint(1)', |
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| 45 | Schema::TYPE_MONEY => 'decimal(19,4)', |
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| 46 | ]; |
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| 47 | |||
| 48 | |||
| 49 | /** |
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| 50 | * Builds a SQL statement for renaming a column. |
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| 51 | * @param string $table the table whose column is to be renamed. The name will be properly quoted by the method. |
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| 52 | * @param string $oldName the old name of the column. The name will be properly quoted by the method. |
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| 53 | * @param string $newName the new name of the column. The name will be properly quoted by the method. |
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| 54 | * @return string the SQL statement for renaming a DB column. |
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| 55 | * @throws Exception |
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| 56 | */ |
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| 57 | public function renameColumn($table, $oldName, $newName) |
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| 58 | { |
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| 59 | $quotedTable = $this->db->quoteTableName($table); |
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| 60 | $row = $this->db->createCommand('SHOW CREATE TABLE ' . $quotedTable)->queryOne(); |
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| 61 | if ($row === false) { |
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| 62 | throw new Exception("Unable to find column '$oldName' in table '$table'."); |
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| 63 | } |
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| 64 | if (isset($row['Create Table'])) { |
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| 65 | $sql = $row['Create Table']; |
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| 66 | } else { |
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| 67 | $row = array_values($row); |
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| 68 | $sql = $row[1]; |
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| 69 | } |
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| 70 | if (preg_match_all('/^\s*`(.*?)`\s+(.*?),?$/m', $sql, $matches)) { |
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| 71 | foreach ($matches[1] as $i => $c) { |
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| 72 | if ($c === $oldName) { |
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| 73 | return "ALTER TABLE $quotedTable CHANGE " |
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| 74 | . $this->db->quoteColumnName($oldName) . ' ' |
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| 75 | . $this->db->quoteColumnName($newName) . ' ' |
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| 76 | . $matches[2][$i]; |
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| 77 | } |
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| 78 | } |
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| 79 | } |
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| 80 | // try to give back a SQL anyway |
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| 81 | return "ALTER TABLE $quotedTable CHANGE " |
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| 82 | . $this->db->quoteColumnName($oldName) . ' ' |
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| 83 | . $this->db->quoteColumnName($newName); |
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| 84 | } |
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| 85 | |||
| 86 | /** |
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| 87 | * @inheritdoc |
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| 88 | * @see https://bugs.mysql.com/bug.php?id=48875 |
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| 89 | */ |
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| 90 | public function createIndex($name, $table, $columns, $unique = false) |
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| 98 | |||
| 99 | /** |
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| 100 | * Builds a SQL statement for dropping a foreign key constraint. |
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| 101 | * @param string $name the name of the foreign key constraint to be dropped. The name will be properly quoted by the method. |
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| 102 | * @param string $table the table whose foreign is to be dropped. The name will be properly quoted by the method. |
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| 103 | * @return string the SQL statement for dropping a foreign key constraint. |
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| 104 | */ |
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| 105 | public function dropForeignKey($name, $table) |
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| 110 | |||
| 111 | /** |
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| 112 | * Builds a SQL statement for removing a primary key constraint to an existing table. |
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| 113 | * @param string $name the name of the primary key constraint to be removed. |
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| 114 | * @param string $table the table that the primary key constraint will be removed from. |
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| 115 | * @return string the SQL statement for removing a primary key constraint from an existing table. |
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| 116 | */ |
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| 117 | public function dropPrimaryKey($name, $table) |
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| 118 | { |
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| 119 | return 'ALTER TABLE ' . $this->db->quoteTableName($table) . ' DROP PRIMARY KEY'; |
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| 120 | } |
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| 121 | |||
| 122 | /** |
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| 123 | * Creates a SQL statement for resetting the sequence value of a table's primary key. |
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| 124 | * The sequence will be reset such that the primary key of the next new row inserted |
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| 125 | * will have the specified value or 1. |
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| 126 | * @param string $tableName the name of the table whose primary key sequence will be reset |
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| 127 | * @param mixed $value the value for the primary key of the next new row inserted. If this is not set, |
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| 128 | * the next new row's primary key will have a value 1. |
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| 129 | * @return string the SQL statement for resetting sequence |
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| 130 | * @throws InvalidParamException if the table does not exist or there is no sequence associated with the table. |
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| 131 | */ |
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| 132 | 1 | public function resetSequence($tableName, $value = null) |
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| 133 | { |
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| 134 | 1 | $table = $this->db->getTableSchema($tableName); |
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| 135 | if ($table !== null && $table->sequenceName !== null) { |
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| 136 | $tableName = $this->db->quoteTableName($tableName); |
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| 137 | if ($value === null) { |
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| 138 | $key = reset($table->primaryKey); |
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| 139 | $value = $this->db->createCommand("SELECT MAX(`$key`) FROM $tableName")->queryScalar() + 1; |
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| 140 | } else { |
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| 141 | $value = (int) $value; |
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| 142 | } |
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| 143 | |||
| 144 | return "ALTER TABLE $tableName AUTO_INCREMENT=$value"; |
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| 145 | } elseif ($table === null) { |
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| 146 | throw new InvalidParamException("Table not found: $tableName"); |
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| 147 | } else { |
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| 148 | throw new InvalidParamException("There is no sequence associated with table '$tableName'."); |
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| 149 | } |
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| 150 | } |
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| 151 | |||
| 152 | /** |
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| 153 | * Builds a SQL statement for enabling or disabling integrity check. |
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| 154 | * @param bool $check whether to turn on or off the integrity check. |
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| 155 | * @param string $schema the schema of the tables. Meaningless for MySQL. |
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| 156 | * @param string $table the table name. Meaningless for MySQL. |
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| 157 | * @return string the SQL statement for checking integrity |
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| 158 | */ |
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| 159 | public function checkIntegrity($check = true, $schema = '', $table = '') |
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| 163 | |||
| 164 | /** |
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| 165 | * @inheritdoc |
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| 166 | */ |
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| 167 | 98 | public function buildLimit($limit, $offset) |
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| 168 | { |
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| 169 | 98 | $sql = ''; |
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| 170 | 98 | if ($this->hasLimit($limit)) { |
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| 171 | $sql = 'LIMIT ' . $limit; |
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| 172 | if ($this->hasOffset($offset)) { |
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| 173 | $sql .= ' OFFSET ' . $offset; |
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| 174 | } |
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| 175 | 98 | } elseif ($this->hasOffset($offset)) { |
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| 176 | // limit is not optional in MySQL |
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| 177 | // http://stackoverflow.com/a/271650/1106908 |
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| 178 | // http://dev.mysql.com/doc/refman/5.0/en/select.html#idm47619502796240 |
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| 179 | $sql = "LIMIT $offset, 18446744073709551615"; // 2^64-1 |
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| 180 | } |
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| 181 | |||
| 182 | 98 | return $sql; |
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| 183 | } |
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| 184 | |||
| 185 | /** |
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| 186 | * @inheritdoc |
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| 187 | */ |
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| 188 | 98 | protected function hasLimit($limit) |
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| 193 | |||
| 194 | /** |
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| 195 | * @inheritdoc |
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| 196 | */ |
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| 197 | 98 | protected function hasOffset($offset) |
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| 203 | |||
| 204 | /** |
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| 205 | * @inheritdoc |
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| 206 | */ |
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| 207 | public function insert($table, $columns, &$params) |
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| 208 | { |
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| 209 | $schema = $this->db->getSchema(); |
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| 210 | if (($tableSchema = $schema->getTableSchema($table)) !== null) { |
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| 211 | $columnSchemas = $tableSchema->columns; |
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| 212 | } else { |
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| 213 | $columnSchemas = []; |
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| 214 | } |
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| 215 | $names = []; |
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| 216 | $placeholders = []; |
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| 217 | $values = ' DEFAULT VALUES'; |
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| 218 | if ($columns instanceof \yii\db\Query) { |
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| 219 | list($names, $values, $params) = $this->prepareInsertSelectSubQuery($columns, $schema, $params); |
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| 220 | } else { |
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| 221 | foreach ($columns as $name => $value) { |
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| 222 | $names[] = $schema->quoteColumnName($name); |
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| 223 | if ($value instanceof Expression) { |
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| 224 | $placeholders[] = $value->expression; |
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| 225 | foreach ($value->params as $n => $v) { |
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| 226 | $params[$n] = $v; |
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| 227 | } |
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| 228 | } elseif ($value instanceof \yii\db\Query) { |
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| 229 | list($sql, $params) = $this->build($value, $params); |
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| 230 | $placeholders[] = "($sql)"; |
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| 231 | } else { |
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| 232 | $phName = self::PARAM_PREFIX . count($params); |
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| 233 | $placeholders[] = $phName; |
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| 234 | $params[$phName] = !is_array($value) && isset($columnSchemas[$name]) ? $columnSchemas[$name]->dbTypecast($value) : $value; |
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| 235 | } |
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| 236 | } |
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| 237 | if (empty($names) && $tableSchema !== null) { |
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| 238 | $columns = !empty($tableSchema->primaryKey) ? $tableSchema->primaryKey : [reset($tableSchema->columns)->name]; |
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| 239 | foreach ($columns as $name) { |
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| 240 | $names[] = $schema->quoteColumnName($name); |
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| 241 | $placeholders[] = 'DEFAULT'; |
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| 242 | } |
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| 243 | } |
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| 244 | } |
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| 245 | |||
| 246 | return 'INSERT INTO ' . $schema->quoteTableName($table) |
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| 247 | . (!empty($names) ? ' (' . implode(', ', $names) . ')' : '') |
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| 248 | . (!empty($placeholders) ? ' VALUES (' . implode(', ', $placeholders) . ')' : $values); |
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| 249 | } |
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| 250 | |||
| 251 | /** |
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| 252 | * @inheritdoc |
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| 253 | * @since 2.0.8 |
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| 254 | */ |
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| 255 | 1 | public function addCommentOnColumn($table, $column, $comment) |
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| 256 | { |
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| 257 | 1 | $definition = $this->getColumnDefinition($table, $column); |
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| 258 | $definition = trim(preg_replace("/COMMENT '(.*?)'/i", '', $definition)); |
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| 259 | |||
| 260 | return 'ALTER TABLE ' . $this->db->quoteTableName($table) |
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| 261 | . ' CHANGE ' . $this->db->quoteColumnName($column) |
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| 262 | . ' ' . $this->db->quoteColumnName($column) |
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| 263 | . (empty($definition) ? '' : ' ' . $definition) |
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| 264 | . ' COMMENT ' . $this->db->quoteValue($comment); |
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| 265 | } |
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| 266 | |||
| 267 | /** |
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| 268 | * @inheritdoc |
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| 269 | * @since 2.0.8 |
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| 270 | */ |
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| 271 | 1 | public function addCommentOnTable($table, $comment) |
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| 275 | |||
| 276 | /** |
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| 277 | * @inheritdoc |
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| 278 | * @since 2.0.8 |
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| 279 | */ |
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| 280 | public function dropCommentFromColumn($table, $column) |
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| 284 | |||
| 285 | /** |
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| 286 | * @inheritdoc |
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| 287 | * @since 2.0.8 |
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| 288 | */ |
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| 289 | public function dropCommentFromTable($table) |
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| 293 | |||
| 294 | |||
| 295 | /** |
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| 296 | * Gets column definition. |
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| 297 | * |
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| 298 | * @param string $table table name |
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| 299 | * @param string $column column name |
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| 300 | * @return null|string the column definition |
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| 301 | * @throws Exception in case when table does not contain column |
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| 302 | */ |
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| 303 | 1 | private function getColumnDefinition($table, $column) |
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| 325 | } |
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| 326 |