oci8po.class.php

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<?php // $Id: oci8po.class.php,v 1.38.2.1 2008/04/26 22:45:04 stronk7 Exp $

///////////////////////////////////////////////////////////////////////////
//                                                                       //
// NOTICE OF COPYRIGHT                                                   //
//                                                                       //
// Moodle - Modular Object-Oriented Dynamic Learning Environment         //
//          http://moodle.com                                            //
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// Copyright (C) 1999 onwards Martin Dougiamas        http://dougiamas.com  //
//           (C) 2001-3001 Eloy Lafuente (stronk7) http://contiento.com  //
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// This program is free software; you can redistribute it and/or modify  //
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// 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:                          //
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//          http://www.gnu.org/copyleft/gpl.html                         //
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///////////////////////////////////////////////////////////////////////////

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

class XMLDBoci8po extends XMLDBgenerator {

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

    var $statement_end = "\n/"; // String to be automatically added at the end of each statement
                                // Using "/" because the standard ";" isn't good for stored procedures (triggers)

    var $number_type = 'NUMBER';    // 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)
                                      // Using this whitespace here because Oracle doesn't distinguish empty and null! :-(

    var $drop_default_clause_required = true; //To specify if the generator must use some DEFAULT clause to drop defaults
    var $drop_default_clause = 'NULL'; //The DEFAULT clause required to drop defaults

    var $default_after_null = false;  //To decide if the default clause of each field must go after the null clause

    var $sequence_extra_code = true; //Does the generator need to add extra code to generate the sequence fields
    var $sequence_name = ''; //Particular name for inline sequences in this generator

    var $drop_table_extra_code = true; //Does the generator need to add code after table drop

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

    var $alter_column_sql = 'ALTER TABLE TABLENAME MODIFY (COLUMNSPECS)'; //The SQL template to alter columns

    /**
     * Creates one new XMLDBoci8po
     */
    function XMLDBoci8po() {
        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 ($xmldb_type) {
            case XMLDB_TYPE_INTEGER:    // From http://www.postgresql.org/docs/7.4/interactive/datatype.html
                if (empty($xmldb_length)) {
                    $xmldb_length = 10;
                }
                $dbtype = 'NUMBER(' .  $xmldb_length . ')';
                break;
            case XMLDB_TYPE_NUMBER:
                $dbtype = $this->number_type;
            /// 38 is the max allowed
                if ($xmldb_length > 38) {
                    $xmldb_length = 38;
                }
                if (!empty($xmldb_length)) {
                    $dbtype .= '(' . $xmldb_length;
                    if (!empty($xmldb_decimals)) {
                        $dbtype .= ',' . $xmldb_decimals;
                    }
                    $dbtype .= ')';
                }
                break;
            case XMLDB_TYPE_FLOAT:
                $dbtype = 'NUMBER';
                break;
            case XMLDB_TYPE_CHAR:
                $dbtype = 'VARCHAR2';
                if (empty($xmldb_length)) {
                    $xmldb_length='255';
                }
                $dbtype .= '(' . $xmldb_length . ')';
                break;
            case XMLDB_TYPE_TEXT:
                $dbtype = 'CLOB';
                break;
            case XMLDB_TYPE_BINARY:
                $dbtype = 'BLOB';
                break;
            case XMLDB_TYPE_DATETIME:
                $dbtype = 'DATE';
                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;
    }

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

        $results = array();

        $sequence_name = $this->getNameForObject($xmldb_table->getName(), $xmldb_field->getName(), 'seq');

        $sequence = "CREATE SEQUENCE " . $sequence_name;
        $sequence.= "\n    START WITH 1";
        $sequence.= "\n    INCREMENT BY 1";
        $sequence.= "\n    NOMAXVALUE";

        $results[] = $sequence;

        $results = array_merge($results, $this->getCreateTriggerSQL ($xmldb_table, $xmldb_field));

        return $results;
    }

    /**
     * Returns the code needed to create one trigger for the xmldb_table and xmldb_field passed
     */
    function getCreateTriggerSQL ($xmldb_table, $xmldb_field) {

        $trigger_name = $this->getNameForObject($xmldb_table->getName(), $xmldb_field->getName(), 'trg');
        $sequence_name = $this->getNameForObject($xmldb_table->getName(), $xmldb_field->getName(), 'seq');

        $trigger = "CREATE TRIGGER " . $trigger_name;
        $trigger.= "\n    BEFORE INSERT";
        $trigger.= "\nON " . $this->getTableName($xmldb_table);
        $trigger.= "\n    FOR EACH ROW";
        $trigger.= "\nBEGIN";
        $trigger.= "\n    IF :new." . $this->getEncQuoted($xmldb_field->getName()) . ' IS NULL THEN';
        $trigger.= "\n        SELECT " . $sequence_name . '.nextval INTO :new.' . $this->getEncQuoted($xmldb_field->getName()) . " FROM dual;";
        $trigger.= "\n    END IF;";
        $trigger.= "\nEND;";

        return array($trigger);
    }

    /**
     * Returns the code needed to drop one sequence for the xmldb_table and xmldb_field passed
     * Can, optionally, specify if the underlying trigger will be also dropped
     */
    function getDropSequenceSQL ($xmldb_table, $xmldb_field, $include_trigger=false) {

        $sequence_name = $this->getSequenceFromDB($xmldb_table);

        $sequence = "DROP SEQUENCE " . $sequence_name;

        $trigger_name = $this->getTriggerFromDB($xmldb_table);

        $trigger = "DROP TRIGGER " . $trigger_name;

        if ($include_trigger) {
            $result =  array($sequence, $trigger);
        } else {
            $result = array($sequence);
        }
        return $result;
    }

    /**
     * Returns the code (in array) needed to add one comment to the table
     */
    function getCommentSQL ($xmldb_table) {

        $comment = "COMMENT ON TABLE " . $this->getTableName($xmldb_table);
        $comment.= " IS '" . addslashes(substr($xmldb_table->getComment(), 0, 250)) . "'";

        return array($comment);
    }

    /**
     * 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
            $results = array_merge($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 drop
     */
    function getDropTableExtraSQL ($xmldb_table) {
        $xmldb_field = new XMLDBField('id'); // Fields having sequences should be exclusively, id.
        return $this->getDropSequenceSQL($xmldb_table, $xmldb_field, false);
    }

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

        $results = array();

        $xmldb_field = new XMLDBField('id'); // Fields having sequences should be exclusively, id.

        $oldseqname = $this->getSequenceFromDB($xmldb_table);
        $newseqname = $this->getNameForObject($newname, $xmldb_field->getName(), 'seq');

    /// Rename de sequence
        $results[] = 'RENAME ' . $oldseqname . ' TO ' . $newseqname;

        $oldtriggername = $this->getTriggerFromDB($xmldb_table);
        $newtriggername = $this->getNameForObject($newname, $xmldb_field->getName(), 'trg');

    /// Drop old trigger
        $results[] = "DROP TRIGGER " . $oldtriggername;

        $newt = new XMLDBTable($newname); /// Temp table for trigger code generation

    /// Create new trigger
        $results = array_merge($results, $this->getCreateTriggerSQL($newt, $xmldb_field));

    /// Rename all the check constraints in the table
        $oldtablename = $this->getTableName($xmldb_table);
        $newtablename = $this->getTableName($newt);

        $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
     * Oracle has some severe limits:
     *     - clob and blob fields doesn't allow type to be specified
     *     - error is dropped if the null/not null clause is specified and hasn't changed
     *     - changes in precision/decimals of numeric fields drop an ORA-1440 error
     */
    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));
        $metac = $meta[$fieldname];
        $oldtype = strtolower($metac->type);
        $oldmetatype = column_type($xmldb_table->getName(), $fieldname);
        $oldlength = $metac->max_length;
    /// To calculate the oldlength if the field is numeric, we need to perform one extra query
    /// because ADOdb has one bug here. http://phplens.com/lens/lensforum/msgs.php?id=15883
        if ($oldmetatype == 'N') {
            $uppertablename = strtoupper($tablename);
            $upperfieldname = strtoupper($fieldname);
            if ($col = get_record_sql("SELECT cname, precision
                                   FROM col
                                   WHERE tname = '$uppertablename'
                                     AND cname = '$upperfieldname'")) {
                $oldlength = $col->precision;
            }
        }
        $olddecimals = empty($metac->scale) ? null : $metac->scale;
        $oldnotnull = empty($metac->not_null) ? false : $metac->not_null;
        $olddefault = empty($metac->default_value) || strtoupper($metac->default_value) == 'NULL' ? null : $metac->default_value;

        $typechanged = true;  //By default, assume that the column type has changed