Complex classes like MySQLi 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 MySQLi, and based on these observations, apply Extract Interface, too.
1 | <?php |
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12 | class MySQLi extends _Abstract { |
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13 | /** |
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14 | * @var \MySQLi Instance of DB connection |
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15 | */ |
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16 | protected $instance; |
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17 | /** |
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18 | * @inheritdoc |
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19 | */ |
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20 | 24 | public function __construct ($database, $user = '', $password = '', $host = 'localhost', $prefix = '') { |
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21 | 24 | $start = microtime(true); |
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22 | /** |
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23 | * Parsing of $host variable, detecting port and persistent connection |
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24 | */ |
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25 | 24 | list($host, $port) = $this->get_host_and_port($host); |
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26 | 24 | $this->instance = new \MySQLi($host, $user, $password, $database, $port); |
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27 | 24 | if (!is_object($this->instance) || $this->instance->connect_errno) { |
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28 | 1 | return; |
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29 | } |
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30 | 24 | $this->database = $database; |
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31 | /** |
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32 | * Changing DB charset if necessary |
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33 | */ |
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34 | 24 | if ($this->instance->character_set_name() != 'utf8mb4') { |
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35 | 24 | $this->instance->set_charset('utf8mb4'); |
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36 | } |
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37 | 24 | $this->connected = true; |
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38 | 24 | $this->connecting_time = microtime(true) - $start; |
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39 | 24 | $this->db_type = 'mysql'; |
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40 | 24 | $this->prefix = $prefix; |
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41 | 24 | } |
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42 | /** |
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43 | * Parse host string into host and port separately |
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44 | * |
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45 | * Understands `p:` prefix for persistent connections |
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46 | * |
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47 | * @param string $host_string |
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48 | * |
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49 | * @return array |
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50 | */ |
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51 | 24 | protected function get_host_and_port ($host_string) { |
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71 | /** |
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72 | * @inheritdoc |
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73 | * |
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74 | * @return bool|mysqli_result |
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75 | */ |
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76 | 24 | protected function q_internal ($query, $parameters = []) { |
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93 | /** |
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94 | * @param string $query |
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95 | * @param array $parameters |
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96 | * |
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97 | * @return bool|mysqli_result |
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98 | */ |
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99 | 24 | protected function q_internal_internal ($query, $parameters) { |
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116 | /** |
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117 | * @inheritdoc |
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118 | * |
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119 | * @param false|mysqli_result $query_result |
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120 | */ |
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121 | 23 | public function f ($query_result, $single_column = false, $array = false, $indexed = false) { |
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140 | /** |
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141 | * @inheritdoc |
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142 | */ |
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143 | 17 | public function id () { |
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146 | /** |
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147 | * @inheritdoc |
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148 | */ |
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149 | 1 | public function affected () { |
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152 | /** |
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153 | * @inheritdoc |
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154 | * |
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155 | * @param false|mysqli_result $query_result |
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156 | */ |
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157 | 20 | public function free ($query_result) { |
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163 | /** |
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164 | * @inheritdoc |
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165 | */ |
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166 | 2 | public function columns ($table, $like = false) { |
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178 | /** |
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179 | * @inheritdoc |
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180 | */ |
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181 | 1 | public function tables ($like = false) { |
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189 | /** |
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190 | * @inheritdoc |
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191 | */ |
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192 | 22 | protected function s_internal ($string, $single_quotes_around) { |
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196 | /** |
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197 | * @inheritdoc |
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198 | */ |
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199 | 1 | public function server () { |
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202 | /** |
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203 | * @inheritdoc |
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204 | */ |
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205 | 2 | public function __destruct () { |
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211 | } |
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212 |