Complex classes like Database 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 Database, and based on these observations, apply Extract Interface, too.
1 | <?php |
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14 | final class Database implements DBInterface{ |
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15 | protected $db; |
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16 | public $sql; |
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17 | private $key; |
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18 | |||
19 | protected $logLocation; |
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20 | public $logErrors = true; |
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21 | public $logQueries = false; |
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22 | public $displayErrors = false; |
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23 | |||
24 | protected $database; |
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25 | protected $cacheEnabled = false; |
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26 | protected $cacheObj; |
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27 | protected $cacheValue; |
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28 | protected $modified = false; |
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29 | |||
30 | private $query; |
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31 | private $values = []; |
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32 | private $prepare = []; |
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33 | |||
34 | private static $connectors = array( |
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35 | 'cubrid' => 'cubrid:host=%s;port=%d;dbname=%s', |
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36 | 'dblib' => 'dblib:host=%s:%d;dbname=%s', |
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37 | 'mssql' => 'sqlsrv:Server=%s,%d;Database=%s', |
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38 | 'mysql' => 'mysql:host=%s;port=%d;dbname=%s', |
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39 | 'pgsql' => 'pgsql:host=%s;port=%d;dbname=%s', |
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40 | 'sqlite' => 'sqlite::memory:' |
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41 | ); |
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42 | |||
43 | /** |
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44 | * Connect to database using PDO connection |
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45 | * @param string $hostname This should be the host of the database e.g. 'localhost' |
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46 | * @param string $username This should be the username for the chosen database |
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47 | * @param string $password This should be the password for the chosen database |
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48 | * @param string $database This should be the database that you wish to connect to |
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49 | * @param string|false $backuphost If you have a replication server set up put the hostname or IP address incase the primary server goes down |
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50 | * @param object|false $cache If you want to cache the queries with Memcache(d)/Redis/APC/Xcache This should be the object else set to false |
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51 | * @param boolean $persistent If you want a persistent database connection set to true |
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52 | * @param string $type The type of connection that you wish to make can be 'mysql', 'cubrid', 'dblib', 'mssql', 'odbc', 'pgsql, or 'sqlite' |
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53 | * @param int $port This should be the port number of the MySQL database connection |
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54 | */ |
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55 | 1 | public function __construct($hostname, $username, $password, $database, $backuphost = false, $cache = false, $persistent = false, $type = 'mysql', $port = 3306) { |
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70 | |||
71 | /** |
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72 | * Closes the PDO database connection when Database object unset |
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73 | */ |
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74 | 1 | public function __destruct() { |
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75 | 1 | $this->closeDatabase(); |
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76 | 1 | } |
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77 | |||
78 | /** |
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79 | * Connect to the database using PDO connection |
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80 | * @param string $username This should be the username for the chosen database |
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81 | * @param string $password This should be the password for the chosen database |
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82 | * @param string $database This should be the database that you wish to connect to |
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83 | * @param string $hostname The hostname for the database |
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84 | * @param boolean $persistent If you want a persistent database connection set to true |
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85 | * @param string $type The type of connection that you wish to make can be 'mysql', 'cubrid', 'dblib', 'mssql', 'pgsql, or 'sqlite' |
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86 | * @param int $port The port number to connect to the MySQL server |
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87 | */ |
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88 | 2 | protected function connectToServer($username, $password, $database, $hostname, $persistent = false, $type = 'mysql', $port = 3306) { |
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100 | |||
101 | /** |
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102 | * Enables the caching and set the caching object to the one provided |
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103 | * @param object $caching This should be class of the type of caching you are using |
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104 | */ |
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105 | 1 | public function setCaching($caching) { |
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112 | |||
113 | /** |
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114 | * This query function is used for more advanced SQL queries for which non of the other methods fit |
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115 | * @param string $sql This should be the SQL query which you wish to run |
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116 | * @param array $variables This should be an array of values to execute as the values in a prepared statement |
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117 | * @return array Returns array of results for the query that has just been run |
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118 | */ |
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119 | 1 | public function query($sql, $variables = array(), $cache = true) { |
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134 | |||
135 | /** |
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136 | * Returns a single record for a select query for the chosen table |
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137 | * @param string $table This should be the table you wish to select the values from |
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138 | * @param array $where Should be the field names and values you wish to use as the where query e.g. array('fieldname' => 'value', 'fieldname2' => 'value2', etc). |
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139 | * @param string|array $fields This should be the records you wis to select from the table. It should be either set as '*' which is the default or set as an array in the following format array('field', 'field2', 'field3', etc). |
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140 | * @param array $order This is the order you wish the results to be ordered in should be formatted as follows array('fieldname' => 'ASC') or array("'fieldname', 'fieldname2'" => 'DESC') |
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141 | * @param boolean $cache If the query should be cached or loaded from cache set to true else set to false |
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142 | * @return array Returns a single table record as the standard array when running SQL queries |
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143 | */ |
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144 | 1 | public function select($table, $where = array(), $fields = '*', $order = array(), $cache = true) { |
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147 | |||
148 | /** |
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149 | * Returns a multidimensional array of the results from the selected table given the given parameters |
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150 | * @param string $table This should be the table you wish to select the values from |
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151 | * @param array $where Should be the field names and values you wish to use as the where query e.g. array('fieldname' => 'value', 'fieldname2' => 'value2', etc). |
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152 | * @param string|array $fields This should be the records you wis to select from the table. It should be either set as '*' which is the default or set as an array in the following format array('field', 'field2', 'field3', etc). |
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153 | * @param array $order This is the order you wish the results to be ordered in should be formatted as follows array('fieldname' => 'ASC') or array("'fieldname', 'fieldname2'" => 'DESC') |
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154 | * @param integer|array $limit The number of results you want to return 0 is default and returns all results, else should be formated either as a standard integer or as an array as the start and end values e.g. array(0 => 150) |
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155 | * @param boolean $cache If the query should be cached or loaded from cache set to true else set to false |
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156 | * @return array Returns a multidimensional array with the chosen fields from the table |
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157 | */ |
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158 | 3 | public function selectAll($table, $where = array(), $fields = '*', $order = array(), $limit = 0, $cache = true) { |
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168 | |||
169 | /** |
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170 | * Returns a single column value for a given query |
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171 | * @param string $table This should be the table you wish to select the values from |
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172 | * @param array $where Should be the field names and values you wish to use as the where query e.g. array('fieldname' => 'value', 'fieldname2' => 'value2', etc). |
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173 | * @param array $fields This should be the records you wis to select from the table. It should be either set as '*' which is the default or set as an array in the following format array('field', 'field2', 'field3', etc). |
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174 | * @param int $colNum This should be the column number you wish to get (starts at 0) |
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175 | * @param array $order This is the order you wish the results to be ordered in should be formatted as follows array('fieldname' => 'ASC') or array("'fieldname', 'fieldname2'" => 'DESC') so it can be done in both directions |
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176 | * @param boolean $cache If the query should be cached or loaded from cache set to true else set to false |
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177 | * @return mixed If a result is found will return the value of the colum given else will return false |
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178 | */ |
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179 | 2 | public function fetchColumn($table, $where = array(), $fields = '*', $colNum = 0, $order = array(), $cache = true) { |
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189 | |||
190 | /** |
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191 | * Inserts into database using the prepared PDO statements |
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192 | * @param string $table This should be the table you wish to insert the values into |
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193 | * @param array $records This should be the field names and values in the format of array('fieldname' => 'value', 'fieldname2' => 'value2', etc.) |
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194 | * @return boolean If data is inserted returns true else returns false |
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195 | */ |
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196 | 2 | public function insert($table, $records) { |
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203 | |||
204 | /** |
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205 | * Updates values in a database using the provide variables |
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206 | * @param string $table This should be the table you wish to update the values for |
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207 | * @param array $records This should be the field names and new values in the format of array('fieldname' => 'newvalue', 'fieldname2' => 'newvalue2', etc.) |
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208 | * @param array $where Should be the field names and values you wish to update in the form of an array e.g. array('fieldname' => 'value', 'fieldname2' => 'value2', etc). |
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209 | * @param int $limit The number of results you want to return 0 is default and will update all results that match the query, else should be formated as a standard integer |
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210 | * @return boolean Returns true if update is successful else returns false |
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211 | */ |
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212 | 2 | public function update($table, $records, $where = array(), $limit = 0) { |
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217 | |||
218 | /** |
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219 | * Deletes records from the given table based on the variables given |
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220 | * @param string $table This should be the table you wish to delete the records from |
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221 | * @param array $where This should be an array of for the where statement |
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222 | * @param int $limit The number of results you want to return 0 is default and will delete all results that match the query, else should be formated as a standard integer |
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223 | */ |
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224 | 2 | public function delete($table, $where, $limit = 0) { |
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229 | |||
230 | /** |
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231 | * Count the number of return results |
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232 | * @param string $table The table you wish to count the result of |
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233 | * @param array $where Should be the field names and values you wish to use as the where query e.g. array('fieldname' => 'value', 'fieldname2' => 'value2', etc). |
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234 | * @param boolean $cache If the query should be cached or loaded from cache set to true else set to false |
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235 | * @return int Returns the number of results |
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236 | */ |
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237 | 1 | public function count($table, $where = array(), $cache = true) { |
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248 | |||
249 | /** |
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250 | * Truncates a given table from the selected database so there are no values in the table |
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251 | * @param string $table This should be the table you wish to truncate |
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252 | * @return boolean If the table is emptied returns true else returns false |
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253 | */ |
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254 | 1 | public function truncate($table) { |
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264 | |||
265 | /** |
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266 | * Returns the number of rows for the last query sent |
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267 | * @return int Returns the number of rows for the last query |
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268 | */ |
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269 | 8 | public function numRows() { |
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275 | |||
276 | /** |
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277 | * Returns the number of rows for the last query sent (Looks a the numRows() function just added incase of habbit) |
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278 | * @return int Returns the number of rows for the last query |
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279 | */ |
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280 | 1 | public function rowCount() { |
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283 | |||
284 | /** |
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285 | * Returns the ID of the last record last inserted |
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286 | * @param string $name This should be the name of the sequence object you wish to retrieve |
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287 | * @return int|string Returns the last inserted ID of the last insert item if $name is null else returns string with sequenced object |
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288 | */ |
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289 | 1 | public function lastInsertId($name = null) { |
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292 | |||
293 | /** |
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294 | * Checks to see if a connection has been made to the server |
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295 | * @return boolean |
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296 | */ |
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297 | 2 | public function isConnected() { |
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300 | |||
301 | /** |
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302 | * Returns the server version information |
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303 | */ |
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304 | 1 | public function serverVersion() { |
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307 | |||
308 | /** |
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309 | * Sets the location of the log files |
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310 | * @param string $location This should be where you wish the logs to be stored |
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311 | * @return $this |
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312 | */ |
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313 | 1 | public function setLogLocation($location = false) { |
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323 | |||
324 | /** |
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325 | * Displays the error massage which occurs |
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326 | * @param \Exception $error This should be an instance of Exception |
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327 | */ |
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328 | 4 | private function error($error) { |
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339 | |||
340 | /** |
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341 | * Writes all queries to a log file |
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342 | */ |
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343 | public function writeQueryToLog() { |
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349 | |||
350 | /** |
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351 | * Closes the PDO database connection by setting the connection to NULL |
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352 | */ |
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353 | 1 | public function closeDatabase() { |
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356 | |||
357 | /** |
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358 | * Build the SQL query but doesn't execute it |
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359 | * @param string $table This should be the table you wish to select the values from |
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360 | * @param array $where Should be the field names and values you wish to use as the where query e.g. array('fieldname' => 'value', 'fieldname2' => 'value2', etc). |
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361 | * @param string|array $fields This should be the records you wis to select from the table. It should be either set as '*' which is the default or set as an array in the following format array('field', 'field2', 'field3', etc). |
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362 | * @param array $order This is the order you wish the results to be ordered in should be formatted as follows array('fieldname' => 'ASC') or array("'fieldname', 'fieldname2'" => 'DESC') so it can be done in both directions |
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363 | * @param integer|array $limit The number of results you want to return 0 is default and returns all results, else should be formated either as a standard integer or as an array as the start and end values e.g. array(0 => 150) |
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364 | */ |
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365 | 5 | protected function buildSelectQuery($table, $where = array(), $fields = '*', $order = array(), $limit = 0) { |
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378 | |||
379 | /** |
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380 | * Execute the current query if no cache value is available |
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381 | * @param boolean $cache If the cache should be checked for the checked for the values of the query set to true else set to false |
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382 | * @return mixed If a cached value exists will be returned else if cache is not checked and query is executed will not return anything |
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383 | */ |
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384 | 13 | protected function executeQuery($cache = true) { |
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402 | |||
403 | /** |
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404 | * This outputs the SQL where query based on a given array |
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405 | * @param array $where This should be an array that you wish to create the where query for in the for array('field1' => 'test') or array('field1' => array('>=', 0)) |
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406 | * @return string|false If the where query is an array will return the where string and set the values else returns false if no array sent |
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407 | */ |
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408 | 9 | private function where($where) { |
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420 | |||
421 | /** |
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422 | * Sets the order sting for the SQL query based on an array or string |
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423 | * @param array|string $order This should be either set to array('fieldname' => 'ASC/DESC') or RAND() |
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424 | * @return string|false If the SQL query has an valid order by will return a string else returns false |
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425 | */ |
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426 | 1 | private function orderBy($order) { |
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444 | |||
445 | /** |
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446 | * Build the field list for the query |
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447 | * @param array $records This should be an array listing all of the fields |
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448 | * @param boolean $insert If this is an insert statement should be set to true to create the correct amount of queries for the prepared statement |
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449 | * @return string The fields list will be returned as a string to insert into the SQL query |
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450 | */ |
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451 | 4 | private function fields($records, $insert = false) { |
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466 | |||
467 | /** |
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468 | * Returns the limit SQL for the current query as a string |
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469 | * @param integer|array $limit This should either be set as an integer or should be set as an array with a start and end value |
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470 | * @return string|false Will return the LIMIT string for the current query if it is valid else returns false |
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471 | */ |
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472 | 1 | private function limit($limit = 0) { |
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483 | |||
484 | |||
485 | /** |
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486 | * Set the cache with a key and value |
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487 | * @param string $key The unique key to store the value against |
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488 | * @param mixed $value The value of the MYSQL query |
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489 | */ |
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490 | 2 | public function setCache($key, $value) { |
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495 | |||
496 | /** |
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497 | * Get the results for a given key |
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498 | * @param string $key The unique key to check for stored variables |
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499 | * @return mixed Returned the cached results from |
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500 | */ |
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501 | 2 | public function getCache($key) { |
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508 | |||
509 | /** |
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510 | * Clears the cache |
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511 | */ |
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512 | public function flushDB() { |
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515 | |||
516 | /** |
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517 | * Format the where queries and set the prepared values |
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518 | * @param string $field This should be the field name in the database |
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519 | * @param mixed $value This should be the value which should either be a string or an array if it contains an operator |
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520 | * @return string This should be the string to add to the SQL query |
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521 | */ |
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522 | 8 | protected function formatValues($field, $value) { |
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545 | |||
546 | /** |
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547 | * Band values to use in the query |
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548 | * @param array $values This should be the values being used in the query |
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549 | */ |
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550 | 12 | protected function bindValues($values) { |
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561 | } |
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562 |