mssql.class.php

很棒的在线教学系统

<?php // $Id: mssql.class.php,v 1.41 2007/10/10 05:25:18 nicolasconnault Exp $

///////////////////////////////////////////////////////////////////////////
//                                                                       //
// NOTICE OF COPYRIGHT                                                   //
//                                                                       //
// Moodle - Modular Object-Oriented Dynamic Learning Environment         //
//          http://moodle.com                                            //
//                                                                       //
// Copyright (C) 1999 onwards Martin Dougiamas        http://dougiamas.com  //
//           (C) 2001-3001 Eloy Lafuente (stronk7) http://contiento.com  //
//                                                                       //
// This program is free software; you can redistribute it and/or modify  //
// it under the terms of the GNU General Public License as published by  //
// the Free Software Foundation; either version 2 of the License, or     //
// (at your option) any later version.                                   //
//                                                                       //
// This program is distributed in the hope that it will be useful,       //
// but WITHOUT ANY WARRANTY; without even the implied warranty of        //
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         //
// GNU General Public License for more details:                          //
//                                                                       //
//          http://www.gnu.org/copyleft/gpl.html                         //
//                                                                       //
///////////////////////////////////////////////////////////////////////////

/// This class generate SQL code to be used against MSSQL
/// It extends XMLDBgenerator so everything can be
/// overriden as needed to generate correct SQL.

class XMLDBmssql extends XMLDBgenerator {

/// Only set values that are different from the defaults present in XMLDBgenerator

    var $statement_end = "\ngo"; // String to be automatically added at the end of each statement

    var $number_type = 'DECIMAL';    // Proper type for NUMBER(x) in this DB

    var $unsigned_allowed = false;    // To define in the generator must handle unsigned information
    var $default_for_char = '';      // To define the default to set for NOT NULLs CHARs without default (null=do nothing)

    var $specify_nulls = true;  //To force the generator if NULL clauses must be specified. It shouldn't be necessary
                                     //but some mssql drivers require them or everything is created as NOT NULL :-(

    var $sequence_extra_code = false; //Does the generator need to add extra code to generate the sequence fields
    var $sequence_name = 'IDENTITY(1,1)'; //Particular name for inline sequences in this generator
    var $sequence_only = false; //To avoid to output the rest of the field specs, leaving only the name and the sequence_name variable

    var $enum_inline_code = false; //Does the generator need to add inline code in the column definition

    var $add_table_comments  = false;  // Does the generator need to add code for table comments

    var $concat_character = '+'; //Characters to be used as concatenation operator. If not defined
                                  //MySQL CONCAT function will be use

    var $rename_table_sql = "sp_rename 'OLDNAME', 'NEWNAME'"; //SQL sentence to rename one table, both
                                  //OLDNAME and NEWNAME are dinamically replaced

    var $rename_table_extra_code = true; //Does the generator need to add code after table rename

    var $rename_column_extra_code = true; //Does the generator need to add code after field rename

    var $rename_column_sql = "sp_rename 'TABLENAME.OLDFIELDNAME', 'NEWFIELDNAME', 'COLUMN'";
                                      ///TABLENAME, OLDFIELDNAME and NEWFIELDNAME are dianmically replaced

    var $drop_index_sql = 'DROP INDEX TABLENAME.INDEXNAME'; //SQL sentence to drop one index
                                                               //TABLENAME, INDEXNAME are dinamically replaced

    var $rename_index_sql = "sp_rename 'TABLENAME.OLDINDEXNAME', 'NEWINDEXNAME', 'INDEX'"; //SQL sentence to rename one index
                                      //TABLENAME, OLDINDEXNAME, NEWINDEXNAME are dinamically replaced

    var $rename_key_sql = null; //SQL sentence to rename one key
                                          //TABLENAME, OLDKEYNAME, NEWKEYNAME are dinamically replaced

    /**
     * Creates one new XMLDBmssql
     */
    function XMLDBmssql() {
        parent::XMLDBgenerator();
        $this->prefix = '';
        $this->reserved_words = $this->getReservedWords();
    }

    /**
     * Given one XMLDB Type, lenght and decimals, returns the DB proper SQL type
     */
    function getTypeSQL ($xmldb_type, $xmldb_length=null, $xmldb_decimals=null) {

        switch ($xmldb_type) {
            case XMLDB_TYPE_INTEGER:    // From http://msdn.microsoft.com/library/en-us/tsqlref/ts_da-db_7msw.asp?frame=true
                if (empty($xmldb_length)) {
                    $xmldb_length = 10;
                }
                if ($xmldb_length > 9) {
                    $dbtype = 'BIGINT';
                } else if ($xmldb_length > 4) {
                    $dbtype = 'INTEGER';
                } else {
                    $dbtype = 'SMALLINT';
                }
                break;
            case XMLDB_TYPE_NUMBER:
                $dbtype = $this->number_type;
                if (!empty($xmldb_length)) {
                /// 38 is the max allowed
                    if ($xmldb_length > 38) {
                        $xmldb_length = 38;
                    }
                    $dbtype .= '(' . $xmldb_length;
                    if (!empty($xmldb_decimals)) {
                        $dbtype .= ',' . $xmldb_decimals;
                    }
                    $dbtype .= ')';
                }
                break;
            case XMLDB_TYPE_FLOAT:
                $dbtype = 'FLOAT';
                if (!empty($xmldb_decimals)) {
                    if ($xmldb_decimals < 6) {
                        $dbtype = 'REAL';
                    }
                }
                break;
            case XMLDB_TYPE_CHAR:
                $dbtype = 'NVARCHAR';
                if (empty($xmldb_length)) {
                    $xmldb_length='255';
                }
                $dbtype .= '(' . $xmldb_length . ')';
                break;
            case XMLDB_TYPE_TEXT:
                $dbtype = 'NTEXT';
                break;
            case XMLDB_TYPE_BINARY:
                $dbtype = 'IMAGE';
                break;
            case XMLDB_TYPE_DATETIME:
                $dbtype = 'DATETIME';
                break;
        }
        return $dbtype;
    }

    /**
     * Returns the code needed to create one enum for the xmldb_table and xmldb_field passes
     */
    function getEnumExtraSQL ($xmldb_table, $xmldb_field) {

        $sql = 'CONSTRAINT ' . $this->getNameForObject($xmldb_table->getName(), $xmldb_field->getName(), 'ck');
        $sql.= ' CHECK (' . $this->getEncQuoted($xmldb_field->getName()) . ' IN (' . implode(', ', $xmldb_field->getEnumValues()) . '))';

        return $sql;
    }

    /**
     * Given one XMLDBTable and one XMLDBField, return the SQL statements needded to drop the field from the table
     * MSSQL overwrites the standard sentence because it needs to do some extra work dropping the default and
     * check constraints
     */
    function getDropFieldSQL($xmldb_table, $xmldb_field) {

        global $db;

        $results = array();

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

    /// Look for any default constraint in this field and drop it
        if ($defaultname = $this->getDefaultConstraintName($xmldb_table, $xmldb_field)) {
            $results[] = 'ALTER TABLE ' . $tablename . ' DROP CONSTRAINT ' . $defaultname;
        }

    /// Look for any check constraint in this field and drop it
        if ($drop_check = $this->getDropEnumSQL($xmldb_table, $xmldb_field)) {
            $results = array_merge($results, $drop_check);
        }

    /// Build the standard alter table drop column
        $results[] = 'ALTER TABLE ' . $tablename . ' DROP COLUMN ' . $fieldname;

        return $results;
    }

    /**
     * Given one correct XMLDBField and the new name, returns the SQL statements
     * to rename it (inside one array)
     * MSSQL is special, so we overload the function here. It needs to
     * drop the constraints BEFORE renaming the field
     */
    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();
        }

    /// Drop the check constraint if exists
        if ($xmldb_field->getEnum()) {
            $results = array_merge($results, $this->getDropEnumSQL($xmldb_table, $xmldb_field));
        }

    /// Call to standard (parent) getRenameFieldSQL() function
        $results = array_merge($results, parent::getRenameFieldSQL($xmldb_table, $xmldb_field, $newname));

        return $results;
    }

    /**
     * Returns the code (array of statements) needed to execute extra statements on field rename
     */
    function getRenameFieldExtraSQL ($xmldb_table, $xmldb_field, $newname) {

        $results = array();

    /// If the field is enum, drop and re-create the check constraint
        if ($xmldb_field->getEnum()) {
        /// Drop the current enum (not needed, it has been dropped before for msqql (in getRenameFieldSQL)
            //$results = array_merge($results, $this->getDropEnumSQL($xmldb_table, $xmldb_field));
        /// Change field name (over a clone to avoid some potential problems later)
            $new_xmldb_field = clone($xmldb_field);
            $new_xmldb_field->setName($newname);

        /// Recreate the enum
            $results = array_merge($results, $this->getCreateEnumSQL($xmldb_table, $new_xmldb_field));
        }

        return $results;
    }

    /**
     * Returns the code (array of statements) needed to execute extra statements on table rename
     */
    function getRenameTableExtraSQL ($xmldb_table, $newname) {

        $results = array();

        $newt = new XMLDBTable($newname); //Temporal table for name calculations

        $oldtablename = $this->getTableName($xmldb_table);
        $newtablename = $this->getTableName($newt);

    /// Rename all the check constraints in the table
        $oldconstraintprefix = $this->getNameForObject($xmldb_table->getName(), '');
        $newconstraintprefix = $this->getNameForObject($newt->getName(), '', '');

        if ($constraints = $this->getCheckConstraintsFromDB($xmldb_table)) {
            foreach ($constraints as $constraint) {
            /// Drop the old constraint
                $results[] = 'ALTER TABLE ' . $newtablename . ' DROP CONSTRAINT ' . $constraint->name;
            /// Calculate the new constraint name
                $newconstraintname = str_replace($oldconstraintprefix, $newconstraintprefix, $constraint->name);
            /// Add the new constraint
                $results[] = 'ALTER TABLE ' . $newtablename . ' ADD CONSTRAINT ' . $newconstraintname .
                             ' CHECK ' . $constraint->description;
            }
        }

        return $results;
    }

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

        global $db;

        $results = array(); /// To store all the needed SQL commands

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

    /// Take a look to field metadata
        $meta = array_change_key_case($db->MetaColumns($tablename));