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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22 | class Db |
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23 | { |
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24 | /** |
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25 | * Database handle/connection. |
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26 | * |
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27 | * @var PDO |
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28 | */ |
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29 | protected $pdo; |
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30 | |||
31 | /** |
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32 | * @var string |
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33 | */ |
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34 | protected $dsn; |
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35 | |||
36 | /** |
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37 | * @var string |
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38 | */ |
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39 | protected $username; |
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40 | |||
41 | /** |
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42 | * @var string |
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43 | */ |
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44 | protected $password; |
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45 | |||
46 | /** |
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47 | * @var array |
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48 | */ |
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49 | protected $options; |
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50 | |||
51 | /** |
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52 | * @var bool |
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53 | */ |
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54 | protected $hasActiveTransaction = false; |
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55 | |||
56 | /** |
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57 | * Constructor. |
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58 | * |
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59 | * @param string|PDO $hostDsnOrPdo A MySQL host, a dsn or an existing PDO instance. |
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60 | * @param string|null $username |
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61 | * @param string|null $password |
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62 | * @param string|null $database |
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63 | * @param array $options |
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64 | */ |
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65 | 19 | public function __construct( |
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66 | $hostDsnOrPdo, |
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67 | $username = null, |
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68 | $password = null, |
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69 | $database = null, |
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70 | array $options = [] |
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71 | ) { |
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72 | 19 | if ($hostDsnOrPdo instanceof PDO) { |
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73 | 19 | $this->pdo = $hostDsnOrPdo; |
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74 | 19 | } elseif (strpos($hostDsnOrPdo, ':') !== false) { |
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75 | $this->dsn = $hostDsnOrPdo; |
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76 | } else { |
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77 | $this->dsn = "mysql:host={$hostDsnOrPdo}" . ($database ? ";dbname={$database}" : ''); |
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78 | } |
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79 | |||
80 | 19 | $this->username = $username; |
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81 | 19 | $this->password = $password; |
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82 | 19 | $this->options = $options; |
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83 | 19 | } |
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84 | |||
85 | /** |
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86 | */ |
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87 | 13 | public function connect() |
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88 | { |
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89 | 13 | if ($this->isConnected()) { |
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90 | 13 | return; |
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91 | } |
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92 | |||
93 | $retries = isset($this->options['connectRetries'])? $this->options['connectRetries'] : 0; |
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94 | do { |
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95 | try { |
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96 | $defaultPdoOptions = [ |
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97 | PDO::ATTR_TIMEOUT => 5, |
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98 | // We want emulation by default (faster for single queries). Disable if you want to |
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99 | // use proper native prepared statements |
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100 | PDO::ATTR_EMULATE_PREPARES => true, |
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101 | PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION, |
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102 | PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC, |
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103 | ]; |
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104 | $pdoOptions = $defaultPdoOptions + (isset($this->options['pdo']) ? $this->options['pdo'] : []); |
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105 | |||
106 | $this->pdo = new PDO( |
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107 | $this->dsn, |
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108 | $this->username, |
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109 | $this->password, |
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110 | $pdoOptions |
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111 | ); |
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112 | |||
113 | return; |
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114 | } catch (PDOException $e) { |
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115 | if ($this->isConnectionExceptionCausedByConnection($e) && $retries > 0) { |
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116 | // Sleep for 100 - 500 ms until next retry |
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117 | usleep(rand(100000, 500000)); |
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118 | } else { |
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119 | throw new ConnectionException($e); |
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120 | } |
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121 | } |
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122 | |||
123 | } while ($retries-- > 0); |
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124 | } |
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125 | |||
126 | /** |
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127 | * @param PDOException $exception |
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128 | * @return bool |
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129 | */ |
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130 | private function isConnectionExceptionCausedByConnection(PDOException $exception) |
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131 | { |
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132 | return in_array($exception->getCode(), [ |
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133 | 2002, // Can't connect to MySQL server (Socket) |
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134 | 2003, // Can't connect to MySQL server (TCP) |
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135 | 2006, // MySQL server has gone away |
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136 | 2013, // Lost connection to MySQL server during query |
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137 | ]); |
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138 | } |
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139 | |||
140 | /** |
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141 | * Close the database connection. |
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142 | */ |
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143 | 1 | public function disconnect() |
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144 | { |
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145 | 1 | $this->pdo = null; |
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146 | 1 | } |
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147 | |||
148 | /** |
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149 | */ |
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150 | 1 | public function reconnect() |
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151 | { |
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152 | 1 | $this->disconnect(); |
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153 | 1 | $this->connect(); |
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154 | 1 | } |
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155 | |||
156 | /** |
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157 | * Check if database connection is open. |
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158 | * |
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159 | * @return bool |
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160 | */ |
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161 | 14 | public function isConnected() |
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162 | { |
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163 | 14 | return ($this->pdo instanceof PDO); |
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164 | } |
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165 | |||
166 | /** |
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167 | * Returns the PDO handle. |
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168 | * |
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169 | * Can be used to gain access to any special PDO methods. |
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170 | * |
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171 | * @return PDO |
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172 | */ |
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173 | 2 | public function getPdo() |
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174 | { |
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175 | 2 | return $this->pdo; |
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176 | } |
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177 | |||
178 | /** |
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179 | * Creates and executes a PDO statement. |
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180 | * |
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181 | * @param string $sql |
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182 | * @param array $parameters |
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183 | * @return PDOStatement |
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184 | */ |
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185 | 5 | protected function executeQuery($sql, array $parameters = []) |
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186 | { |
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187 | 5 | $this->connect(); |
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188 | |||
189 | try { |
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190 | 5 | $pdoStatement = $this->pdo->prepare($sql); |
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191 | 4 | $pdoStatement->execute($this->prepareParameters($parameters)); |
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192 | |||
193 | 4 | return $pdoStatement; |
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194 | 1 | } catch (PDOException $e) { |
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195 | 1 | throw new QueryException($e, $sql, $parameters); |
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196 | } |
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197 | } |
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198 | |||
199 | /** |
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200 | * Execute an SQL statement and return the number of affected rows. |
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201 | * |
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202 | * @param string $sql |
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203 | * @param array $parameters |
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204 | * @return int The number of rows affected |
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205 | */ |
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206 | 2 | public function exec($sql, array $parameters = []) |
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207 | { |
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208 | 2 | $statement = $this->executeQuery($sql, $parameters); |
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209 | |||
210 | 1 | return $statement->rowCount(); |
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211 | } |
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212 | |||
213 | /** |
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214 | * Execute an SQL statement and return the first row. |
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215 | * |
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216 | * @param string $sql |
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217 | * @param array $parameters |
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218 | * @param bool $indexedKeys |
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219 | * @return array|false |
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220 | */ |
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221 | 1 | public function fetchRow($sql, array $parameters = [], $indexedKeys = false) |
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222 | { |
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223 | 1 | $statement = $this->executeQuery($sql, $parameters); |
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224 | |||
225 | 1 | return $statement->fetch($indexedKeys ? PDO::FETCH_NUM : PDO::FETCH_ASSOC); |
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226 | } |
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227 | |||
228 | /** |
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229 | * Execute an SQL statement and return all rows as an array. |
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230 | * |
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231 | * @param string $sql |
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232 | * @param array $parameters |
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233 | * @param bool $indexedKeys |
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234 | * @return array |
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235 | */ |
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236 | 1 | public function fetchRows($sql, array $parameters = [], $indexedKeys = false) |
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242 | |||
243 | /** |
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244 | * Execute an SQL statement and return the first column of the first row. |
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245 | * |
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246 | * @param string $sql |
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247 | * @param array $parameters |
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248 | * @return string|false |
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249 | */ |
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250 | 1 | public function fetchValue($sql, array $parameters = []) |
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256 | |||
257 | /** |
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258 | * Quote a value for a safe use in query (eg. bla'bla -> 'bla''bla'). |
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259 | * |
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260 | * @param mixed $value |
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261 | * @return string |
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262 | */ |
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263 | 1 | public function quote($value) |
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264 | { |
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265 | 1 | $this->connect(); |
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266 | |||
269 | |||
270 | /** |
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271 | * Get id of the last inserted row. |
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272 | * |
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273 | * @return int |
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274 | */ |
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275 | 1 | public function getLastInsertId() |
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281 | |||
282 | /** |
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283 | * Prepare parameters for database use. |
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284 | * |
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285 | * @param array $parameters |
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286 | * @return array |
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287 | */ |
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288 | 4 | protected function prepareParameters(array $parameters = []) |
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303 | |||
304 | /** |
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305 | * Begin transaction (turns off autocommit mode). |
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306 | 4 | * |
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307 | * @param bool $onlyIfNoActiveTransaction |
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308 | 4 | * @return bool |
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309 | */ |
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310 | 4 | public function beginTransaction($onlyIfNoActiveTransaction = false) |
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323 | 2 | ||
324 | /** |
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325 | 2 | * Commits current active transaction (restores autocommit mode). |
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326 | */ |
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327 | 2 | public function commit() |
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334 | 2 | ||
335 | /** |
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336 | 2 | * Rolls back current active transaction (restores autocommit mode). |
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337 | */ |
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338 | 2 | public function rollBack() |
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345 | 3 | ||
346 | /** |
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347 | 3 | * @return bool |
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348 | */ |
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349 | public function hasActiveTransaction() |
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353 | |||
354 | /** |
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355 | 1 | * @param string $table |
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356 | * @param array $data |
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357 | 1 | * @return int The number of rows affected |
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358 | 1 | */ |
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359 | public function insert($table, array $data) |
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371 | |||
372 | /** |
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373 | * @param string $table |
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374 | * @param array $data |
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375 | 1 | * @param string $whereSql |
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376 | * @param array $whereParameters |
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377 | 1 | * @return int The number of rows affected |
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378 | 1 | */ |
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379 | 1 | public function update($table, array $data, $whereSql = '', array $whereParameters = []) |
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395 | } |
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396 |