Sync.php

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<?php


class DB_Sync {

        var $db1;
        var $db2;
        
        var $table1;
        var $table2;

        var $table1Data;
        var $table2Data;
        
        var $renamed = array();
        var $listeners = array();
        
        function DB_Sync($db1, $db2, $table1=null, $table2=null, $renamed=null){
                $this->db1 = $db1;
                $this->db2 = $db2;
                
                $this->init($table1, $table2, $renamed);
        }

        
        function equals($table1=null, $table2=null){
                
                $this->init($table1,$table2);
                echo "Now here";
                print_r($this->table1Data);
                print_r($this->table2Data);
                return ( $this->table1Data == $this->table2Data );
                
        }
        
        function init($table1, $table2, $renamed=null){
                
                if ( isset($table1) and isset($table2) and ($table1 != $this->table1 || $table2 != $this->table2) ){
                        
                        
                        $this->table1 = $table1;
                        $this->table2 = $table2;
                        if ( isset($renamed) ) $this->renamed = $renamed;
                        $this->loadTableData();
                        
                }
        }
        
        function checkTableNames(){
        
                if ( !isset($this->table1) ){
                        trigger_error("Attempt to load data for tables in DB_Sync, but table 1 has not been specified.", E_USER_ERROR);
                }
                
                if ( !isset($this->table2) ){
                        trigger_error("Attempt to load data for tables in DB_Sync, but table 2 has not been specified.", E_USER_ERROR);
                }
                
                if ( !preg_match('/^[a-zA-Z0-9_]+$/', $this->table1) ){
                        trigger_error("The table '{$this->table1}' has an invalid name.", E_USER_ERROR);
                }
                
                if ( !preg_match('/^[a-zA-Z0-9_]+$/', $this->table2) ){
                        trigger_error("The table '{$this->table2}' has an invalid name.", E_USER_ERROR);
                }
        
        }
        
        
        
        function loadTableData(){
        
                $this->checkTableNames();
                
                $res = mysql_query("show full fields from `".$this->table1."`", $this->db1);
                if ( !$res ) trigger_error(mysql_error($this->db1));
                
                
                $this->table1Data = array();
                while ( $row = mysql_fetch_assoc($res) ){
                        $this->table1Data[$row['Field']] = $row;
                }
                
                @mysql_free_result($res);
                
                
                $res = mysql_query("show columns from `".$this->table2."`", $this->db2);
                if ( !$res ) trigger_error(mysql_error($this->db2));
                
                $this->table2Data = array();
                while ( $row = mysql_fetch_assoc($res) ){
                        $this->table2Data[$row['Field']] = $row;
                }
                
                @mysql_free_result($res);
                
                
        }
        
        function fieldArrayToSQLDef($field){
        
                if ( $field['Default']  ){
                
                        if ( strcasecmp($field['Default'], 'NULL') === 0 ){
                        
                                $default = 'default NULL';
                                
                        } else if ( $field['Default'] ) {
                        
                                $default = 'default \''.$field['Default'].'\'';
                        } else {
                                $default = '';
                        }
                        
                } else {
                
                        $default = '';
                        
                }
                
                if ( $field['Collation'] and strcasecmp($field['Collation'],'null') !== 0){
                
                        $charset = 'CHARACTER SET '.substr($field['Collation'],0, strpos($field['Collation'], '_')).' COLLATE '.
                                                $field['Collation'];
                                                
                }       else {
                
                        $charset = '';
                }
                
                if ( $field['Null'] ){
                
                        $null = ( ( strcasecmp('yes',$field['Null'])===0 ) ? '' : 'NOT NULL');
                } else {
                        $null = '';
                }
                
                
                
                
                
                return "`{$field['Field']}` {$field['Type']} {$charset} {$null} {$field['Extra']} {$default}";
        
        }
        
        function syncField($fieldname, $after=null, $renameMap=null){
                
                if (isset($renameMap) ) $this->renamed = $renameMap;
                
                
                
                if ( !isset($this->table1Data[$fieldname]) ){
                        
                        // Table 1 does not have this field... see if it has been renamed.
                        
                        if ( isset($this->renamed[$fieldname]) ){
                                
                                $newname = @$this->renamed[$fieldname];
                                
                                if ( !$newname ){
                                        trigger_error("Attempt to rename field '{$fieldname}' in table '{$this->table2}' to {$newname} but the source table '{$this->table1}' has no such field to copy.", E_USER_ERROR);
                                }
                                
                                $sql = "alter table `{$this->table2}` change `{$fieldname}` ".$this->fieldArrayToSQLDef($this->table1Data[$newname]);
                                $res = mysql_query($sql, $this->db2);
                                if ( !$res ) trigger_error(mysql_error($this->db2), E_USER_ERROR);
                                
                        } else {
                        
                                trigger_error("Attempt to syncronize field '{$fieldname}' but the source table has no such field.", E_USER_ERROR);
                        }
                        
                        
                } else if ( !isset( $this->table2Data[$fieldname] ) ) {
                
                        $sql = "alter table `{$this->table2}` add ".$this->fieldArrayToSQLDef($this->table1Data[$fieldname]);
                        if ( isset($after) ){
                                $sql .= "after `{$after}`";
                        }
                        $res = mysql_query($sql, $this->db2);
                        if ( !$res ) trigger_error($sql."\n".mysql_error($this->db2), E_USER_ERROR);
                        
                } else if ( $this->table1Data[$fieldname] != $this->table2Data[$fieldname] ) {
                        
                        $sql = "alter table `{$this->table2}` change `{$fieldname}` ".$this->fieldArrayToSQLDef($this->table1Data[$fieldname]);
                        $res = mysql_query($sql, $this->db2);
                        if ( !$res ) trigger_error(mysql_error($this->db2), E_USER_ERROR);
                        
                } else {
                
                        // nothing to do here.
                }
        }
        
        
        
        function syncTables($table1=null, $table2=null, $renamedMap=null){
                
                $this->init($table1, $table2, $renamedMap);
                
                if (!$this->equals() ){
                        echo "Here";
                        $positions = array();
                        $fieldnames = array_keys($this->table1Data);
                        $i=0;
                        foreach ($fieldnames as $f){
                                $positions[$f] = $i++;
                                
                        }
                        
                        $fields = array_merge(array_keys($this->table1Data), array_keys($this->table2Data));
                        $fields = array_unique($fields);
                        print_r($fields);
                        foreach ($fields as $field ){
                                if ( isset( $positions[$field] ) and $positions[$field] > 0 ){
                                        $after = $fieldnames[$positions[$field]-1];
                                } else if ( isset($positions[$field]) ){
                                        $after = "first";
                                } else {
                                        $after = null;
                                }
                                $this->syncField($field, $after);
                        }
                }
                
                
                
        
        }
}

?>