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, $newName) |
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85 | |||
86 | /** |
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87 | * @inheritdoc |
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88 | * @see https://bugs.mysql.com/bug.php?id=48875 |
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89 | */ |
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90 | public function createIndex($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 $value the value for the primary key of the next new row inserted. If this is not set, |
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128 | * the next new row's primary key will have a value 1. |
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129 | * @return string the SQL statement for resetting sequence |
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130 | * @throws InvalidParamException if the table does not exist or there is no sequence associated with the table. |
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131 | */ |
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132 | public function resetSequence($tableName, $value = null) |
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133 | { |
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134 | $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 = '', $table = '') |
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160 | { |
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161 | return 'SET FOREIGN_KEY_CHECKS = ' . ($check ? 1 : 0); |
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162 | } |
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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 $sql; |
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183 | } |
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184 | |||
185 | /** |
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186 | * @inheritdoc |
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187 | */ |
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188 | public function insert($table, $columns, &$params) |
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189 | { |
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190 | $schema = $this->db->getSchema(); |
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191 | if (($tableSchema = $schema->getTableSchema($table)) !== null) { |
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192 | $columnSchemas = $tableSchema->columns; |
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193 | } else { |
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194 | $columnSchemas = []; |
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195 | } |
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196 | $names = []; |
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197 | $placeholders = []; |
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198 | foreach ($columns as $name => $value) { |
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199 | $names[] = $schema->quoteColumnName($name); |
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200 | if ($value instanceof Expression) { |
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201 | $placeholders[] = $value->expression; |
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202 | foreach ($value->params as $n => $v) { |
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203 | $params[$n] = $v; |
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204 | } |
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205 | } else { |
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206 | $phName = self::PARAM_PREFIX . count($params); |
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207 | $placeholders[] = $phName; |
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208 | $params[$phName] = !is_array($value) && isset($columnSchemas[$name]) ? $columnSchemas[$name]->dbTypecast($value) : $value; |
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209 | } |
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210 | } |
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211 | if (empty($names) && $tableSchema !== null) { |
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212 | $columns = !empty($tableSchema->primaryKey) ? $tableSchema->primaryKey : [reset($tableSchema->columns)->name]; |
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213 | foreach ($columns as $name) { |
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214 | $names[] = $schema->quoteColumnName($name); |
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215 | $placeholders[] = 'DEFAULT'; |
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216 | } |
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217 | } |
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218 | |||
219 | return 'INSERT INTO ' . $schema->quoteTableName($table) |
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220 | . (!empty($names) ? ' (' . implode(', ', $names) . ')' : '') |
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221 | . (!empty($placeholders) ? ' VALUES (' . implode(', ', $placeholders) . ')' : ' DEFAULT VALUES'); |
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222 | } |
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223 | |||
224 | /** |
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225 | * @inheritdoc |
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226 | * @since 2.0.8 |
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227 | */ |
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228 | 1 | public function addCommentOnColumn($table, $column, $comment) |
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229 | { |
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230 | 1 | $definition = $this->getColumnDefinition($table, $column); |
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231 | $definition = trim(preg_replace("/COMMENT '(.*?)'/i", '', $definition)); |
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232 | |||
233 | return 'ALTER TABLE ' . $this->db->quoteTableName($table) |
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234 | . ' CHANGE ' . $this->db->quoteColumnName($column) |
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235 | . ' ' . $this->db->quoteColumnName($column) |
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236 | . (empty($definition) ? '' : ' ' . $definition) |
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237 | . ' COMMENT ' . $this->db->quoteValue($comment); |
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238 | } |
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239 | |||
240 | /** |
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241 | * @inheritdoc |
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242 | * @since 2.0.8 |
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243 | */ |
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244 | 1 | public function addCommentOnTable($table, $comment) |
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248 | |||
249 | /** |
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250 | * @inheritdoc |
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251 | * @since 2.0.8 |
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252 | */ |
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253 | public function dropCommentFromColumn($table, $column) |
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257 | |||
258 | /** |
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259 | * @inheritdoc |
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260 | * @since 2.0.8 |
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261 | */ |
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262 | public function dropCommentFromTable($table) |
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266 | |||
267 | |||
268 | /** |
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269 | * Gets column definition. |
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270 | * |
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271 | * @param string $table table name |
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272 | * @param string $column column name |
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273 | * @return null|string the column definition |
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274 | * @throws Exception in case when table does not contain column |
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275 | */ |
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276 | 1 | private function getColumnDefinition($table, $column) |
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298 | } |
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299 |