MetadataTool.php

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<?php
import('Dataface/Table.php');

class Dataface_MetadataTool {
        
        var $fieldDefs = null;
        
        var $tablename = null;
        
        var $columns = null;
        
        var $keyColumns = null;
        
        function Dataface_MetadataTool($tablename){
                $this->tablename = $tablename;
        }
        
        function isMetadataTable($tablename=null){
                if ( !isset($tablename) ) $tablename = $this->tablename;
                return (strstr( $tablename, '__metadata') == '__metadata');
        
        }
        
        function &getColumns($tablename=null, $usecache=true){
                $app =& Dataface_Application::getInstance();
                if (!isset($tablename) ) $tablename = $this->tablename;
                $md_tablename = $tablename.'__metadata';
                if ( !isset($this->columns) || !$usecache ){
                        $this->columns = array();
                        $sql = "show columns from `".$md_tablename."`";
                        $res = mysql_query($sql, $app->db());
                        if ( !$res ) trigger_error(mysql_error($app->db()), E_USER_ERROR);
                        if ( mysql_num_rows($res) == 0) trigger_error("No metadata table '{$md_tablename}' could be found.", E_USER_ERROR);
                        
                        while ( $row = mysql_fetch_assoc($res) ){
                                $this->columns[$row['Field']] = $row;
                        }
                        @mysql_free_result($res);
                }
                return $this->columns;
        
        }
        
        function &getKeyColumns($tablename=null, $usecache=true){
                if (!isset($tablename) ) $tablename = $this->tablename;
                $md_tablename = $tablename.'__metadata';
                if ( !isset($this->keyColumns) || !$usecache ){
                        $this->keyColumns = array();
                        $cols = $this->getColumns($tablename, $usecache);
                        foreach (array_keys($cols) as $col){
                                if ( strcasecmp($this->columns[$col]['Key'], 'PRI') === 0 ){
                                        $this->keyColumns[$this->columns[$col]['Field']] =& $this->columns[$col];
                                }
                        }
                }
                
                return $this->keyColumns;
                
        }

        
        
        function loadMetadataFieldDefs($tablename=null){
                if ( !isset($tablename) ) $tablename = $this->tablename;
                if ( !isset($this->fieldDefs) ){
                        
                
                        import('Dataface/ConfigTool.php');
                        $configTool =& Dataface_ConfigTool::getInstance();
                        $this->fieldDefs = $configTool->loadConfig('metadata',$tablename);
                        foreach (array_keys($this->fieldDefs) as $key ){
                                $field =& $this->fieldDefs[$key];
                                $field['name'] = '__'.$key;
                                $field['Field'] = $field['name'];
                                if ( !isset($field['Type']) ) $field['Type'] = 'varchar(64)';
                                $this->fieldDefs['__'.$key] =& $field;
                                unset($this->fieldDefs[$key]);
                                unset($field);
                        }
                }
                
                return $this->fieldDefs;
        
        }
        

        function createMetadataTable($tablename=null){
                if ( !isset($tablename) ) $tablename = $this->tablename;
                if ( Dataface_MetadataTool::isMetadataTable($tablename) ) return false;
                $app =& Dataface_Application::getInstance();
                
                $table =& Dataface_Table::loadTable($tablename);
                
                if ( !Dataface_Table::tableExists($tablename.'__metadata', false) ){
                        $sql = "CREATE TABLE `{$tablename}__metadata` (
                                ";
                        foreach ($table->keys() as $field ){
                                $type = (strtolower($field['Type']) != 'container' ? $field['Type'] : 'varchar(64)');
                                
                                $sql .= "`{$field['name']}` {$type} DEFAULT NULL,
                                ";
                                
                        }
                        $metafields = $this->loadMetadataFieldDefs($tablename);
                        foreach ($metafields as $fieldname=>$field){
                                if ( @$field['Default'] ) $default = " DEFAULT '{$field['Default']}'";
                                else $default = '';
                                $sql .= "`{$fieldname}` {$field['Type']}{$default},";
                        }
                        
                        $keynames = array_keys($table->keys());
                        $sql .= "primary key (`".implode('`,`', $keynames)."`))";
                        $res = mysql_query($sql, $app->db());
                        if ( !$res ) trigger_error(mysql_error($res), E_USER_ERROR);
                        return true;
                                
                } 
                
                return false;
                
                
        }
        
        function refreshMetadataTable($tablename=null){
                if ( !isset($tablename) ) $tablename = $this->tablename;
                if ( Dataface_MetadataTool::isMetadataTable($tablename) ) return false;
                $app =& Dataface_Application::getInstance();
                $table =& Dataface_Table::loadTable($tablename);
                $md_tablename = $tablename.'__metadata';
                if ( !Dataface_Table::tableExists($md_tablename, false) ){
                        if ( $this->createMetadataTable($tablename) ) return true;
                }
                $cols =& $this->getColumns($tablename, false);
                
                
                // First we have to go through all of the key fields of the subject table
                // and make sure that they appear in the metadata table.
                $updatePrimaryKey = false;
                foreach ($table->keys() as $field){
                        if ( !isset($cols[$field['Field']]) ){
                                $updatePrimaryKey=true;
                                $default = ( @$field['Default'] ? " DEFAULT {$field['Default']}" : '');
                                $sql = "alter table `{$md_tablename}` add column `{$field['Field']}` {$field['Type']}{$default}";
                                $res = mysql_query($sql, $app->db());
                                if ( !$res ) trigger_error(mysql_error($app->db()), E_USER_ERROR);
                        }
                }
                
                $table_keys =& $table->keys();
                
                //Next we have to go through all of the key fields in the metadata table ane make sure that they
                // appear in the subject table primary keys.
                foreach ($this->getKeyColumns($tablename, false) as $field){
                        if ( !isset($table_keys[$field['Field']]) ){
                                $updatePrimaryKey = true;
                                $sql = "alter table `{$md_tablename}` drop column `{$field['Field']}`";
                                $res = mysql_query($sql, $app->db());
                                if ( !$res ) trigger_error(mysql_error($app->db()), E_USER_ERROR);
                        }
                }
                
                // If the primary key needed to be updated, we will update it now.
                if ( $updatePrimaryKey ){
                        // The primary key needs to be updated
                        $sql = "drop primary key";
                        @mysql_query($sql, $app->db());
                        $sql = "alter table `{$md_tablename}` add primary key (`".implode('`,`',array_keys($table->keys()))."`)";
                        $res = mysql_query($sql, $app->db());
                        if ( !$res ) trigger_error(mysql_error($app->db()), E_USER_ERROR);
                
                }
                
                // Now we need to make sure that all of the prescribed meta fields are 
                // in the metadata field.
                
                $fielddefs = $this->loadMetadataFieldDefs($tablename);
                $cols = $this->getColumns($tablename, false);
                
                foreach ($fielddefs as $field){
                        if ( !isset($cols[$field['Field']]) ){
                                $default = (@$field['Default'] ? " DEFAULT {$field['Default']}": '');
                                $sql = "alter table `{$md_tablename}` add column `{$field['Field']}` {$field['Type']}{$default}";
                                $res = mysql_query($sql, $app->db());
                                if ( !$res ) trigger_error(mysql_error($app->db()), E_USER_ERROR);
                        }
                }
                return true;
                
        }
}