xmldbgenerator.class.php

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     * Given one XMLDBTable and one XMLDBField, return the SQL statements needded to modify the enum of the field in the table
     */
    function getModifyEnumSQL($xmldb_table, $xmldb_field) {

        $results = array();

    /// Get the quoted name of the table and field
        $tablename = $this->getTableName($xmldb_table);
        $fieldname = $this->getEncQuoted($xmldb_field->getName());

    /// Decide if we are going to create or to drop the enum (based exclusively in the values passed!)
        if (!$xmldb_field->getEnum()) {
            $results = $this->getDropEnumSQL($xmldb_table, $xmldb_field); //Drop
        } else {
            $results = $this->getCreateEnumSQL($xmldb_table, $xmldb_field); //Create/modify
        }

        return $results;
    }

    /**
     * Given one XMLDBTable and one XMLDBField, return the SQL statements needded to modify the default of the field in the table
     */
    function getModifyDefaultSQL($xmldb_table, $xmldb_field) {

        $results = array();

    /// Get the quoted name of the table and field
        $tablename = $this->getTableName($xmldb_table);
        $fieldname = $this->getEncQuoted($xmldb_field->getName());

    /// Decide if we are going to create/modify or to drop the default
        if ($xmldb_field->getDefault() === null) {
            $results = $this->getDropDefaultSQL($xmldb_table, $xmldb_field); //Drop
        } else {
            $results = $this->getCreateDefaultSQL($xmldb_table, $xmldb_field); //Create/modify
        }

        return $results;
    }

    /**
     * Given one correct XMLDBField and the new name, returns the SQL statements
     * to rename it (inside one array)
     */
    function getRenameFieldSQL($xmldb_table, $xmldb_field, $newname) {

        $results = array();  //Array where all the sentences will be stored

    /// Although this is checked in ddllib - rename_field() - double check
    /// that we aren't trying to rename one "id" field. Although it could be
    /// implemented (if adding the necessary code to rename sequences, defaults,
    /// triggers... and so on under each getRenameFieldExtraSQL() function, it's
    /// better to forbide it, mainly because this field is the default PK and
    /// in the future, a lot of FKs can be pointing here. So, this field, more
    /// or less, must be considered inmutable!
        if ($xmldb_field->getName() == 'id') {
            return array();
        }

        $rename = str_replace('TABLENAME', $this->getTableName($xmldb_table), $this->rename_column_sql);
        $rename = str_replace('OLDFIELDNAME', $this->getEncQuoted($xmldb_field->getName()), $rename);
        $rename = str_replace('NEWFIELDNAME', $this->getEncQuoted($newname), $rename);

        $results[] = $rename;

    /// Call to getRenameFieldExtraSQL() if $rename_column_extra_code is enabled (will add some required sentences)
        if ($this->rename_column_extra_code) {
            $extra_sentences = $this->getRenameFieldExtraSQL($xmldb_table, $xmldb_field, $newname);
            $results = array_merge($results, $extra_sentences);
        }

        return $results;
    }

    /**
     * Given one XMLDBTable and one XMLDBKey, return the SQL statements needded to add the key to the table
     * note that undelying indexes will be added as parametrised by $xxxx_keys and $xxxx_index parameters
     */
    function getAddKeySQL($xmldb_table, $xmldb_key) {

        $results = array();

    /// Just use the CreateKeySQL function
        if ($keyclause = $this->getKeySQL($xmldb_table, $xmldb_key)) {
            $key = 'ALTER TABLE ' . $this->getTableName($xmldb_table) .
               ' ADD CONSTRAINT ' . $keyclause;
            $results[] = $key;
        }

    /// If we aren't creating the keys OR if the key is XMLDB_KEY_FOREIGN (not underlying index generated 
    /// automatically by the RDBMS) create the underlying (created by us) index (if doesn't exists)
        if (!$keyclause || $xmldb_key->getType() == XMLDB_KEY_FOREIGN) {
        /// Only if they don't exist
            if ($xmldb_key->getType() == XMLDB_KEY_FOREIGN) {  ///Calculate type of index based on type ok key
                $indextype = XMLDB_INDEX_NOTUNIQUE;
            } else {
                $indextype = XMLDB_INDEX_UNIQUE;
            }
            $xmldb_index = new XMLDBIndex('anyname');
            $xmldb_index->setAttributes($indextype, $xmldb_key->getFields());
            if (!index_exists($xmldb_table, $xmldb_index)) {
                $results = array_merge($results, $this->getAddIndexSQL($xmldb_table, $xmldb_index));
            }
        }

    /// If the key is XMLDB_KEY_FOREIGN_UNIQUE, create it as UNIQUE too
        if ($xmldb_key->getType() == XMLDB_KEY_FOREIGN_UNIQUE && $this->unique_keys) {
        ///Duplicate the key
            $xmldb_key->setType(XMLDB_KEY_UNIQUE);
            $results = array_merge($results, $this->getAddKeySQL($xmldb_table, $xmldb_key));
        }
        
    /// Return results
        return $results;
    }

    /**
     * Given one XMLDBTable and one XMLDBIndex, return the SQL statements needded to drop the index from the table
     */
    function getDropKeySQL($xmldb_table, $xmldb_key) {

        $results = array();

    /// Get the key name (note that this doesn't introspect DB, so could cause some problems sometimes!)
    /// TODO: We'll need to overwrite the whole getDropKeySQL() method inside each DB to do the proper queries
    /// against the dictionary or require ADOdb to support it or change the find_key_name() method to
    /// perform DB introspection directly. But, for now, as we aren't going to enable referential integrity
    /// it won't be a problem at all
        $dbkeyname = find_key_name($xmldb_table, $xmldb_key);

    /// Only if such type of key generation is enabled
        $dropkey = false;
        switch ($xmldb_key->getType()) {
            case XMLDB_KEY_PRIMARY:
                if ($this->primary_keys) {
                    $template = $this->drop_primary_key;
                    $dropkey = true;
                }
                break;
            case XMLDB_KEY_UNIQUE:
                if ($this->unique_keys) {
                    $template = $this->drop_unique_key;
                    $dropkey = true;
                }
                break;
            case XMLDB_KEY_FOREIGN_UNIQUE:
            case XMLDB_KEY_FOREIGN:
                if ($this->foreign_keys) {
                    $template = $this->drop_foreign_key;
                    $dropkey = true;
                }
                break;
        }
    /// If we have decided to drop the key, let's do it
        if ($dropkey) {
        /// Replace TABLENAME, CONSTRAINTTYPE and KEYNAME as needed
            $dropsql = str_replace('TABLENAME', $this->getTableName($xmldb_table), $template);
            $dropsql = str_replace('KEYNAME', $dbkeyname, $dropsql);

            $results[] = $dropsql;
        }

    /// If we aren't dropping the keys OR if the key is XMLDB_KEY_FOREIGN (not underlying index generated 
    /// automatically by the RDBMS) drop the underlying (created by us) index (if exists)
        if (!$dropkey || $xmldb_key->getType() == XMLDB_KEY_FOREIGN) {
        /// Only if they exist
            $xmldb_index = new XMLDBIndex('anyname');
            $xmldb_index->setAttributes(XMLDB_INDEX_UNIQUE, $xmldb_key->getFields());
            if (index_exists($xmldb_table, $xmldb_index)) {
                $results = array_merge($results, $this->getDropIndexSQL($xmldb_table, $xmldb_index));
            }
        }

    /// If the key is XMLDB_KEY_FOREIGN_UNIQUE, drop the UNIQUE too
        if ($xmldb_key->getType() == XMLDB_KEY_FOREIGN_UNIQUE && $this->unique_keys) {
        ///Duplicate the key
            $xmldb_key->setType(XMLDB_KEY_UNIQUE);
            $results = array_merge($results, $this->getDropKeySQL($xmldb_table, $xmldb_key));
        }
        
    /// Return results
        return $results;
    }

    /**
     * Given one XMLDBTable and one XMLDBKey, return the SQL statements needded to rename the key in the table
     * Experimental! Shouldn't be used at all!
     */

    function getRenameKeySQL($xmldb_table, $xmldb_key, $newname) {

        $results = array();

    /// Get the real key name
        $dbkeyname = find_key_name($xmldb_table, $xmldb_key);

    /// Check we are really generating this type of keys
        if (($xmldb_key->getType() == XMLDB_KEY_PRIMARY && !$this->primary_keys) ||
            ($xmldb_key->getType() == XMLDB_KEY_UNIQUE && !$this->unique_keys) ||
            ($xmldb_key->getType() == XMLDB_KEY_FOREIGN && !$this->foreign_keys) ||
            ($xmldb_key->getType() == XMLDB_KEY_FOREIGN_UNIQUE && !$this->unique_keys && !$this->foreign_keys)) {
        /// We aren't generating this type of keys, delegate to child indexes
            $xmldb_index = new XMLDBIndex($xmldb_key->getName());
            $xmldb_index->setFields($xmldb_key->getFields());
            return $this->getRenameIndexSQL($xmldb_table, $xmldb_index, $newname);
        }

    /// Arrived here so we are working with keys, lets rename them
    /// Replace TABLENAME and KEYNAME as needed
        $renamesql = str_replace('TABLENAME', $this->getTableName($xmldb_table), $this->rename_key_sql);
        $renamesql = str_replace('OLDKEYNAME', $dbkeyname, $renamesql);
        $renamesql = str_replace('NEWKEYNAME', $newname, $renamesql);

    /// Some DB doesn't support key renaming so this can be empty
        if ($renamesql) {
            $results[] = $renamesql;
        }

        return $results;
    }

    /**
     * Given one XMLDBTable and one XMLDBIndex, return the SQL statements needded to add the index to the table
     */
    function getAddIndexSQL($xmldb_table, $xmldb_index) {

    /// Just use the CreateIndexSQL function
        return $this->getCreateIndexSQL($xmldb_table, $xmldb_index);
    }

    /**
     * Given one XMLDBTable and one XMLDBIndex, return the SQL statements needded to drop the index from the table
     */
    function getDropIndexSQL($xmldb_table, $xmldb_index) {

        $results = array();

    /// Get the real index name
        $dbindexname = find_index_name($xmldb_table, $xmldb_index);

    /// Replace TABLENAME and INDEXNAME as needed
        $dropsql = str_replace('TABLENAME', $this->getTableName($xmldb_table), $this->drop_index_sql);
        $dropsql = str_replace('INDEXNAME', $dbindexname, $dropsql);

        $results[] = $dropsql;

        return $results;
    }

    /**
     * Given one XMLDBTable and one XMLDBIndex, return the SQL statements needded to rename the index in the table
     * Experimental! Shouldn't be used at all!
     */

    function getRenameIndexSQL($xmldb_table, $xmldb_index, $newname) {

        $results = array();

    /// Get the real index name
        $dbindexname = find_index_name($xmldb_table, $xmldb_index);

    /// Replace TABLENAME and INDEXNAME as needed
        $renamesql = str_replace('TABLENAME', $this->getTableName($xmldb_table), $this->rename_index_sql);
        $renamesql = str_replace('OLDINDEXNAME', $dbindexname, $renamesql);
        $renamesql = str_replace('NEWINDEXNAME', $newname, $renamesql);

    /// Some DB doesn't support index renaming (MySQL) so this can be empty
        if ($renamesql) {
            $results[] = $renamesql;
        }

        return $results;
    }

    /**
     * Given three strings (table name, list of fields (comma separated) and suffix),
     * create the proper object name quoting it if necessary.
     *
     * IMPORTANT: This function must be used to CALCULATE NAMES of objects TO BE CREATED,
     *            NEVER TO GUESS NAMES of EXISTING objects!!!
     */
    function getNameForObject($tablename, $fields, $suffix='') {

        $name = '';

    /// Implement one basic cache to avoid object name duplication
    /// and to speed up repeated queries for the same objects
        if (!isset($used_names)) {
            static $used_names = array();
        }

    /// If this exact object has been requested, return it
        if (array_key_exists($tablename.'-'.$fields.'-'.$suffix, $used_names)) {
            return $used_names[$tablename.'-'.$fields.'-'.$suffix];
        }

    /// Use standard naming. See http://docs.moodle.org/en/XMLDB_key_and_index_naming
        $tablearr = explode ('_', $tablename);
        foreach ($tablearr as $table) {
            $name .= substr(trim($table),0,4);
        }
        $name .= '_';
        $fieldsarr = explode (',', $fields);
        foreach ($fieldsarr as $field) {
            $name .= substr(trim($field),0,3);
        }