| Total Complexity | 48 | 
| Total Lines | 203 | 
| Duplicated Lines | 0 % | 
| Changes | 2 | ||
| Bugs | 0 | Features | 0 | 
Complex classes like DbConn 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.
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 DbConn, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 24 | class DbConn { | 
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| 25 | var $db_conn; // a mysqli object  | 
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| 26 | var $db_name; // the DB name  | 
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| 27 | |||
| 28 |     function init_conn($user, $passwd, $host, $name) { | 
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| 55 | }  | 
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| 56 | |||
| 57 |     function close() { | 
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| 58 |         if ($this->db_conn) { | 
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| 59 | $this->db_conn->close();  | 
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| 60 | }  | 
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| 61 | }  | 
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| 62 | |||
| 63 | // in keeping with PHP/MySQL convention, return true (nonzero) on success.  | 
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| 64 | // (This is the opposite of the BOINC convention)  | 
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| 65 | //  | 
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| 66 |     function do_query($q) { | 
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| 67 | global $generating_xml;  | 
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| 68 |         $q = str_replace('DBNAME', $this->db_name, $q); | 
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| 69 | //echo "query: $q<br>\n";  | 
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| 70 | $ret = $this->db_conn->query($q);  | 
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| 71 |         if (!$ret) { | 
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| 72 |             if (!$generating_xml) { | 
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| 73 | echo "Database Error<br>\n";  | 
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| 74 | }  | 
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| 75 | //echo ": ", $this->base_error(), "\n<pre>";  | 
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| 76 | //var_dump(debug_backtrace());  | 
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| 77 | //echo "</pre>query: $q\n";  | 
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| 78 | return null;  | 
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| 79 | }  | 
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| 80 | return $ret;  | 
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| 81 | }  | 
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| 82 | |||
| 83 | // # rows affected by last query  | 
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| 84 | //  | 
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| 85 |     function affected_rows() { | 
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| 86 | return $this->db_conn->affected_rows;  | 
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| 87 | }  | 
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| 88 | |||
| 89 |     function get_list($table1, $table2, $joinfield1, $joinfield2, $classname, $fields, $where_clause, $order_clause, $limit) { | 
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| 99 | }  | 
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| 100 | |||
| 101 |     function lookup_fields($table, $classname, $fields, $clause) { | 
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| 102 | $query = "select $fields from DBNAME.$table where $clause";  | 
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| 103 | $result = $this->do_query($query);  | 
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| 104 |         if (!$result) { | 
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| 105 | return null;  | 
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| 106 | }  | 
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| 107 | $obj = $result->fetch_object($classname);  | 
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| 108 | $result->free();  | 
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| 109 | return $obj;  | 
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| 110 | }  | 
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| 111 | |||
| 112 |     function lookup($table, $classname, $clause) { | 
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| 113 | return $this->lookup_fields($table, $classname, "*", $clause);  | 
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| 114 | }  | 
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| 115 | |||
| 116 |     function lookup_id($id, $table, $classname) { | 
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| 117 | $id = (int)$id;  | 
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| 118 | return $this->lookup($table, $classname, "id=$id");  | 
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| 119 | }  | 
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| 120 | |||
| 121 |     function enum_general($classname, $query) { | 
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| 122 | $result = $this->do_query($query);  | 
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| 123 | if (!$result) return null;  | 
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| 124 | $x = array();  | 
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| 125 |         while ($obj = $result->fetch_object($classname)) { | 
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| 126 | $x[] = $obj;  | 
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| 127 | }  | 
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| 128 | $result->free();  | 
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| 129 | return $x;  | 
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| 130 | }  | 
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| 131 | |||
| 132 | function enum_fields(  | 
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| 141 | }  | 
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| 142 | |||
| 143 |     function enum($table, $classname, $where_clause=null, $order_clause=null) { | 
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| 144 | return self::enum_fields(  | 
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| 145 | $table, $classname, '*', $where_clause, $order_clause  | 
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| 146 | );  | 
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| 147 | }  | 
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| 148 | |||
| 149 |     function update($obj, $table, $clause) { | 
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| 150 | $query = "update DBNAME.$table set $clause where id=$obj->id";  | 
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| 151 | return $this->do_query($query);  | 
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| 152 | }  | 
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| 153 |     function update_aux($table, $clause) { | 
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| 154 | $query = "update DBNAME.$table set $clause";  | 
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| 155 | return $this->do_query($query);  | 
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| 156 | }  | 
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| 157 |     function insert($table, $clause) { | 
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| 158 | $query = "insert into DBNAME.$table $clause";  | 
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| 159 | return $this->do_query($query);  | 
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| 160 | }  | 
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| 161 |     function delete($obj, $table) { | 
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| 162 | $query = "delete from DBNAME.$table where id=$obj->id";  | 
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| 163 | return $this->do_query($query);  | 
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| 164 | }  | 
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| 165 |     function delete_aux($table, $clause) { | 
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| 166 | $query = "delete from DBNAME.$table where $clause";  | 
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| 167 | return $this->do_query($query);  | 
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| 168 | }  | 
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| 169 |     function insert_id() { | 
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| 170 | return $this->db_conn->insert_id;  | 
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| 171 | }  | 
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| 172 |     function get_int($query, $field) { | 
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| 173 | $result = $this->do_query($query);  | 
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| 174 |         if (!$result) error_page("database error on query $query"); | 
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| 175 |         $x = $result->fetch_object("StdClass"); | 
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| 176 | $result->free();  | 
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| 177 | if ($x) return $x->$field;  | 
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| 178 | return false;  | 
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| 179 | }  | 
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| 180 |     function get_double($query, $field) { | 
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| 181 | $result = $this->do_query($query);  | 
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| 182 |         if (!$result) error_page("database error on query $query"); | 
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| 183 |         $x = $result->fetch_object("StdClass"); | 
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| 184 | $result->free();  | 
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| 185 | if ($x) return (double)$x->$field;  | 
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| 186 | return false;  | 
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| 187 | }  | 
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| 188 |     function count($table, $clause="TRUE") { | 
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| 189 | $query = "select count(*) as total from DBNAME.$table where $clause";  | 
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| 190 | return $this->get_int($query, 'total');  | 
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| 191 | }  | 
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| 192 |     function sum($table, $field, $clause="") { | 
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| 193 | $query = "select sum($field) as total from DBNAME.$table $clause";  | 
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| 194 | return $this->get_double($query, 'total');  | 
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| 195 | }  | 
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| 196 |     function max($table, $field, $clause="") { | 
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| 197 | $query = "select max($field) as total from DBNAME.$table $clause";  | 
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| 198 | return $this->get_double($query, 'total');  | 
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| 199 | }  | 
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| 200 |     function percentile($table, $field, $clause, $pct) { | 
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| 201 | $n = $this->count($table, $clause);  | 
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| 202 | if (!$n) return false;  | 
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| 203 | $m = (int)($n*$pct/100);  | 
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| 204 | $query = "select $field from DBNAME.$table where $clause order by $field limit $m,1";  | 
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| 205 | return $this->get_double($query, $field);  | 
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| 206 | }  | 
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| 207 |     function replace($table, $clause) { | 
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| 208 | $query = "replace into DBNAME.$table set $clause";  | 
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| 209 | return $this->do_query($query);  | 
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| 210 | }  | 
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| 211 |     function base_escape_string($string) { | 
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| 212 | return $this->db_conn->escape_string($string);  | 
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| 213 | }  | 
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| 214 |     function base_error() { | 
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| 215 | return $this->db_conn->error;  | 
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| 216 | }  | 
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| 217 |     function base_errno() { | 
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| 218 | return $this->db_conn->errno;  | 
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| 219 | }  | 
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| 220 |     function table_exists($table_name) { | 
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| 227 | }  | 
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| 228 | }  | 
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| 229 | |||
| 230 | ?>  | 
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| 231 |