adodb-datadict.inc.php

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<?php

/*
    Test script for parser
*/

// security - hide paths
if (!defined('ADODB_DIR')) die();

function Lens_ParseTest()
{
$str = "`zcol ACOL` NUMBER(32,2) DEFAULT 'The \"cow\" (and Jim''s dog) jumps over the moon' PRIMARY, INTI INT AUTO DEFAULT 0, zcol2\"afs ds";
print "<p>$str</p>";
$a= Lens_ParseArgs($str);
print "<pre>";
print_r($a);
print "</pre>";
}


if (!function_exists('ctype_alnum')) {
    function ctype_alnum($text) {
        return preg_match('/^[a-z0-9]*$/i', $text);
    }
}

//Lens_ParseTest();

function Lens_ParseArgs($args,$endstmtchar=',',$tokenchars='_.-')
{
    $pos = 0;
    $intoken = false;
    $stmtno = 0;
    $endquote = false;
    $tokens = array();
    $tokens[$stmtno] = array();
    $max = strlen($args);
    $quoted = false;
    $tokarr = array();

    while ($pos < $max) {
        $ch = substr($args,$pos,1);
        switch($ch) {
        case ' ':
        case "\t":
        case "\n":
        case "\r":
            if (!$quoted) {
                if ($intoken) {
                    $intoken = false;
                    $tokens[$stmtno][] = implode('',$tokarr);
                }
                break;
            }

            $tokarr[] = $ch;
            break;

        case '`':
            if ($intoken) $tokarr[] = $ch;
        case '(':
        case ')':
        case '"':
        case "'":

            if ($intoken) {
                if (empty($endquote)) {
                    $tokens[$stmtno][] = implode('',$tokarr);
                    if ($ch == '(') $endquote = ')';
                    else $endquote = $ch;
                    $quoted = true;
                    $intoken = true;
                    $tokarr = array();
                } else if ($endquote == $ch) {
                    $ch2 = substr($args,$pos+1,1);
                    if ($ch2 == $endquote) {
                        $pos += 1;
                        $tokarr[] = $ch2;
                    } else {
                        $quoted = false;
                        $intoken = false;
                        $tokens[$stmtno][] = implode('',$tokarr);
                        $endquote = '';
                    }
                } else
                    $tokarr[] = $ch;

            }else {

                if ($ch == '(') $endquote = ')';
                else $endquote = $ch;
                $quoted = true;
                $intoken = true;
                $tokarr = array();
                if ($ch == '`') $tokarr[] = '`';
            }
            break;

        default:

            if (!$intoken) {
                if ($ch == $endstmtchar) {
                    $stmtno += 1;
                    $tokens[$stmtno] = array();
                    break;
                }

                $intoken = true;
                $quoted = false;
                $endquote = false;
                $tokarr = array();

            }

            if ($quoted) $tokarr[] = $ch;
            else if (ctype_alnum($ch) || strpos($tokenchars,$ch) !== false) $tokarr[] = $ch;
            else {
                if ($ch == $endstmtchar) {
                    $tokens[$stmtno][] = implode('',$tokarr);
                    $stmtno += 1;
                    $tokens[$stmtno] = array();
                    $intoken = false;
                    $tokarr = array();
                    break;
                }
                $tokens[$stmtno][] = implode('',$tokarr);
                $tokens[$stmtno][] = $ch;
                $intoken = false;
            }
        }
        $pos += 1;
    }
    if ($intoken) $tokens[$stmtno][] = implode('',$tokarr);

    return $tokens;
}


class ADODB_DataDict {
    var $connection;
    var $debug = false;
    var $dropTable = 'DROP TABLE %s';
    var $renameTable = 'RENAME TABLE %s TO %s';
    var $dropIndex = 'DROP INDEX %s';
    var $addCol = ' ADD';
    var $alterCol = ' ALTER COLUMN';
    var $dropCol = ' DROP COLUMN';
    var $renameColumn = 'ALTER TABLE %s RENAME COLUMN %s TO %s';    // table, old-column, new-column, column-definitions (not used by default)
    var $nameRegex = '\w';
    var $nameRegexBrackets = 'a-zA-Z0-9_\(\)';
    var $schema = false;
    var $serverInfo = array();
    var $autoIncrement = false;
    var $dataProvider;
    var $invalidResizeTypes4 = array('CLOB','BLOB','TEXT','DATE','TIME'); // for changetablesql
    var $blobSize = 100;    

    function GetCommentSQL($table,$col)
    {
        return false;
    }

    function SetCommentSQL($table,$col,$cmt)
    {
        return false;
    }

    function MetaTables()
    {
        if (!$this->connection->IsConnected()) return array();
        return $this->connection->MetaTables();
    }

    function MetaColumns($tab, $upper=true, $schema=false)
    {
        if (!$this->connection->IsConnected()) return array();
        return $this->connection->MetaColumns($this->TableName($tab), $upper, $schema);
    }

    function MetaPrimaryKeys($tab,$owner=false,$intkey=false)
    {
        if (!$this->connection->IsConnected()) return array();
        return $this->connection->MetaPrimaryKeys($this->TableName($tab), $owner, $intkey);
    }

    function MetaIndexes($table, $primary = false, $owner = false)
    {
        if (!$this->connection->IsConnected()) return array();
        return $this->connection->MetaIndexes($this->TableName($table), $primary, $owner);
    }

    function MetaType($t,$len=-1,$fieldobj=false)
    {
        static $typeMap = array(
        'VARCHAR' => 'C',
        'VARCHAR2' => 'C',
        'CHAR' => 'C',
        'C' => 'C',
        'STRING' => 'C',
        'NCHAR' => 'C',
        'NVARCHAR' => 'C',
        'VARYING' => 'C',
        'BPCHAR' => 'C',
        'CHARACTER' => 'C',
        'INTERVAL' => 'C',  # Postgres
        'MACADDR' => 'C', # postgres
        'VAR_STRING' => 'C', # mysql
        ##
        'LONGCHAR' => 'X',
        'TEXT' => 'X',
        'NTEXT' => 'X',
        'M' => 'X',
        'X' => 'X',
        'CLOB' => 'X',
        'NCLOB' => 'X',
        'LVARCHAR' => 'X',
        ##
        'BLOB' => 'B',
        'IMAGE' => 'B',
        'BINARY' => 'B',
        'VARBINARY' => 'B',
        'LONGBINARY' => 'B',
        'B' => 'B',
        ##
        'YEAR' => 'D', // mysql
        'DATE' => 'D',
        'D' => 'D',
        ##
        'UNIQUEIDENTIFIER' => 'C', # MS SQL Server
        ##
        'TIME' => 'T',
        'TIMESTAMP' => 'T',
        'DATETIME' => 'T',
        'TIMESTAMPTZ' => 'T',
        'SMALLDATETIME' => 'T',
        'T' => 'T',
        'TIMESTAMP WITHOUT TIME ZONE' => 'T', // postgresql
        ##
        'BOOL' => 'L',
        'BOOLEAN' => 'L',
        'BIT' => 'L',
        'L' => 'L',
        ##
        'COUNTER' => 'R',
        'R' => 'R',
        'SERIAL' => 'R', // ifx
        'INT IDENTITY' => 'R',
        ##
        'INT' => 'I',
        'INT2' => 'I',
        'INT4' => 'I',
        'INT8' => 'I',
        'INTEGER' => 'I',
        'INTEGER UNSIGNED' => 'I',
        'SHORT' => 'I',
        'TINYINT' => 'I',
        'SMALLINT' => 'I',
        'I' => 'I',
        ##
        'LONG' => 'N', // interbase is numeric, oci8 is blob
        'BIGINT' => 'N', // this is bigger than PHP 32-bit integers
        'DECIMAL' => 'N',
        'DEC' => 'N',
        'REAL' => 'N',
        'DOUBLE' => 'N',
        'DOUBLE PRECISION' => 'N',
        'SMALLFLOAT' => 'N',
        'FLOAT' => 'N',
        'NUMBER' => 'N',
        'NUM' => 'N',
        'NUMERIC' => 'N',
        'MONEY' => 'N',

        ## informix 9.2
        'SQLINT' => 'I',
        'SQLSERIAL' => 'I',
        'SQLSMINT' => 'I',
        'SQLSMFLOAT' => 'N',
        'SQLFLOAT' => 'N',
        'SQLMONEY' => 'N',
        'SQLDECIMAL' => 'N',
        'SQLDATE' => 'D',
        'SQLVCHAR' => 'C',
        'SQLCHAR' => 'C',
        'SQLDTIME' => 'T',
        'SQLINTERVAL' => 'N',
        'SQLBYTES' => 'B',
        'SQLTEXT' => 'X',
         ## informix 10
        "SQLINT8" => 'I8',
        "SQLSERIAL8" => 'I8',
        "SQLNCHAR" => 'C',
        "SQLNVCHAR" => 'C',
        "SQLLVARCHAR" => 'X',
        "SQLBOOL" => 'L'
        );

        if (!$this->connection->IsConnected()) {
            $t = strtoupper($t);
            if (isset($typeMap[$t])) return $typeMap[$t];
            return 'N';
        }
        return $this->connection->MetaType($t,$len,$fieldobj);
    }

    function NameQuote($name = NULL,$allowBrackets=false)
    {
        if (!is_string($name)) {
            return FALSE;
        }

        $name = trim($name);

        if ( !is_object($this->connection) ) {
            return $name;
        }

        $quote = $this->connection->nameQuote;

        // if name is of the form `name`, quote it
        if ( preg_match('/^`(.+)`$/', $name, $matches) ) {
            return $quote . $matches[1] . $quote;
        }

        // if name contains special characters, quote it
        $regex = ($allowBrackets) ? $this->nameRegexBrackets : $this->nameRegex;

        if ( !preg_match('/^[' . $regex . ']+$/', $name) ) {
            return $quote . $name . $quote;
        }

        return $name;
    }

    function TableName($name)
    {
        if ( $this->schema ) {
            return $this->NameQuote($this->schema) .'.'. $this->NameQuote($name);
        }
        return $this->NameQuote($name);
    }

    // Executes the sql array returned by GetTableSQL and GetIndexSQL
    function ExecuteSQLArray($sql, $continueOnError = true)
    {
        $rez = 2;
        $conn = $this->connection;
        $saved = $conn->debug;
        foreach($sql as $line) {

            if ($this->debug) $conn->debug = true;
            $ok = $conn->Execute($line);
            $conn->debug = $saved;
            if (!$ok) {
                if ($this->debug) ADOConnection::outp($conn->ErrorMsg());
                if (!$continueOnError) return 0;
                $rez = 1;
            }
        }
        return $rez;
    }

    function ActualType($meta)
    {
        return $meta;
    }

    function CreateDatabase($dbname,$options=false)
    {
        $options = $this->_Options($options);
        $sql = array();

        $s = 'CREATE DATABASE ' . $this->NameQuote($dbname);
        if (isset($options[$this->upperName]))
            $s .= ' '.$options[$this->upperName];

        $sql[] = $s;
        return $sql;
    }

    /*
     Generates the SQL to create index. Returns an array of sql strings.
    */
    function CreateIndexSQL($idxname, $tabname, $flds, $idxoptions = false)
    {
        if (!is_array($flds)) {
            $flds = explode(',',$flds);
        }

        foreach($flds as $key => $fld) {
            # some indexes can use partial fields, eg. index first 32 chars of "name" with NAME(32)
            $flds[$key] = $this->NameQuote($fld,$allowBrackets=true);
        }

        return $this->_IndexSQL($this->NameQuote($idxname), $this->TableName($tabname), $flds, $this->_Options($idxoptions));
    }

    function DropIndexSQL ($idxname, $tabname = NULL)
    {
        return array(sprintf($this->dropIndex, $this->NameQuote($idxname), $this->TableName($tabname)));
    }

    function SetSchema($schema)
    {
        $this->schema = $schema;
    }

    function AddColumnSQL($tabname, $flds)
    {
        $tabname = $this->TableName ($tabname);
        $sql = array();
        list($lines,$pkey,$idxs) = $this->_GenFields($flds);
        // genfields can return FALSE at times
        if ($lines  == null) $lines = array();
        $alter = 'ALTER TABLE ' . $tabname . $this->addCol . ' ';
        foreach($lines as $v) {
            $sql[] = $alter . $v;
        }
        if (is_array($idxs)) {
            foreach($idxs as $idx => $idxdef) {
                $sql_idxs = $this->CreateIndexSql($idx, $tabname, $idxdef['cols'], $idxdef['opts']);
                $sql = array_merge($sql, $sql_idxs);
            }
        }
        return $sql;
    }

    function AlterColumnSQL($tabname, $flds, $tableflds='',$tableoptions='')
    {
        $tabname = $this->TableName ($tabname);
        $sql = array();
        list($lines,$pkey,$idxs) = $this->_GenFields($flds);
        // genfields can return FALSE at times
        if ($lines == null) $lines = array();
        $alter = 'ALTER TABLE ' . $tabname . $this->alterCol . ' ';
        foreach($lines as $v) {
            $sql[] = $alter . $v;
        }
        if (is_array($idxs)) {
            foreach($idxs as $idx => $idxdef) {
                $sql_idxs = $this->CreateIndexSql($idx, $tabname, $idxdef['cols'], $idxdef['opts']);
                $sql = array_merge($sql, $sql_idxs);
            }

        }
        return $sql;
    }

    function RenameColumnSQL($tabname,$oldcolumn,$newcolumn,$flds='')
    {
        $tabname = $this->TableName ($tabname);
        if ($flds) {
            list($lines,$pkey,$idxs) = $this->_GenFields($flds);
            // genfields can return FALSE at times
            if ($lines == null) $lines = array();
            list(,$first) = each($lines);
            list(,$column_def) = preg_split("/[\t ]+/",$first,2);
        }
        return array(sprintf($this->renameColumn,$tabname,$this->NameQuote($oldcolumn),$this->NameQuote($newcolumn),$column_def));
    }

    function DropColumnSQL($tabname, $flds, $tableflds='',$tableoptions='')
    {
        $tabname = $this->TableName ($tabname);
        if (!is_array($flds)) $flds = explode(',',$flds);
        $sql = array();
        $alter = 'ALTER TABLE ' . $tabname . $this->dropCol . ' ';
        foreach($flds as $v) {
            $sql[] = $alter . $this->NameQuote($v);
        }
        return $sql;
    }

    function DropTableSQL($tabname)
    {
        return array (sprintf($this->dropTable, $this->TableName($tabname)));
    }

    function RenameTableSQL($tabname,$newname)
    {
        return array (sprintf($this->renameTable, $this->TableName($tabname),$this->TableName($newname)));
    }

    function CreateTableSQL($tabname, $flds, $tableoptions=array())
    {
        list($lines,$pkey,$idxs) = $this->_GenFields($flds, true);
        // genfields can return FALSE at times
        if ($lines == null) $lines = array();

        $taboptions = $this->_Options($tableoptions);
        $tabname = $this->TableName ($tabname);
        $sql = $this->_TableSQL($tabname,$lines,$pkey,$taboptions);

        // ggiunta - 2006/10/12 - KLUDGE:
        // if we are on autoincrement, and table options includes REPLACE, the
        // autoincrement sequence has already been dropped on table creation sql, so
        // we avoid passing REPLACE to trigger creation code. This prevents
        // creating sql that double-drops the sequence
        if ($this->autoIncrement && isset($taboptions['REPLACE']))
            unset($taboptions['REPLACE']);
        $tsql = $this->_Triggers($tabname,$taboptions);
        foreach($tsql as $s) $sql[] = $s;

        if (is_array($idxs)) {
            foreach($idxs as $idx => $idxdef) {
                $sql_idxs = $this->CreateIndexSql($idx, $tabname,  $idxdef['cols'], $idxdef['opts']);
                $sql = array_merge($sql, $sql_idxs);
            }
        }

        return $sql;
    }



    function _GenFields($flds,$widespacing=false)
    {
        if (is_string($flds)) {
            $padding = '     ';
            $txt = $flds.$padding;
            $flds = array();
            $flds0 = Lens_ParseArgs($txt,',');
            $hasparam = false;
            foreach($flds0 as $f0) {
                $f1 = array();
                foreach($f0 as $token) {
                    switch (strtoupper($token)) {
                    case 'INDEX':
                        $f1['INDEX'] = '';
                        // fall through intentionally
                    case 'CONSTRAINT':
                    case 'DEFAULT':
                        $hasparam = $token;
                        break;
                    default:
                        if ($hasparam) $f1[$hasparam] = $token;
                        else $f1[] = $token;
                        $hasparam = false;
                        break;
                    }
                }
                // 'index' token without a name means single column index: name it after column
                if (array_key_exists('INDEX', $f1) && $f1['INDEX'] == '') {
                    $f1['INDEX'] = isset($f0['NAME']) ? $f0['NAME'] : $f0[0];
                    // check if column name used to create an index name was quoted
                    if (($f1['INDEX'][0] == '"' || $f1['INDEX'][0] == "'" || $f1['INDEX'][0] == "`") &&
                        ($f1['INDEX'][0] == substr($f1['INDEX'], -1))) {
                        $f1['INDEX'] = $f1['INDEX'][0].'idx_'.substr($f1['INDEX'], 1, -1).$f1['INDEX'][0];
                    }
                    else
                        $f1['INDEX'] = 'idx_'.$f1['INDEX'];
                }
                // reset it, so we don't get next field 1st token as INDEX...
                $hasparam = false;

                $flds[] = $f1;

            }
        }
        $this->autoIncrement = false;
        $lines = array();
        $pkey = array();
        $idxs = array();
        foreach($flds as $fld) {
            $fld = _array_change_key_case($fld);

            $fname = false;
            $fdefault = false;
            $fautoinc = false;
            $ftype = false;
            $fsize = false;
            $fprec = false;
            $fprimary = false;
            $fnoquote = false;
            $fdefts = false;
            $fdefdate = false;
            $fconstraint = false;
            $fnotnull = false;
            $funsigned = false;
            $findex = '';
            $funiqueindex = false;

            //-----------------
            // Parse attributes
            foreach($fld as $attr => $v) {
                if ($attr == 2 && is_numeric($v)) $attr = 'SIZE';
                else if (is_numeric($attr) && $attr > 1 && !is_numeric($v)) $attr = strtoupper($v);

                switch($attr) {
                case '0':
                case 'NAME':    $fname = $v; break;
                case '1':
                case 'TYPE':    $ty = $v; $ftype = $this->ActualType(strtoupper($v)); break;

                case 'SIZE':
                                $dotat = strpos($v,'.'); if ($dotat === false) $dotat = strpos($v,',');
                                if ($dotat === false) $fsize = $v;
                                else {
                                    $fsize = substr($v,0,$dotat);
                                    $fprec = substr($v,$dotat+1);
                                }
                                break;
                case 'UNSIGNED': $funsigned = true; break;
                case 'AUTOINCREMENT':
                case 'AUTO':    $fautoinc = true; $fnotnull = true; break;
                case 'KEY':
                // a primary key col can be non unique in itself (if key spans many cols...)
                case 'PRIMARY': $fprimary = $v; $fnotnull = true; /*$funiqueindex = true;*/ break;
                case 'DEF':
                case 'DEFAULT': $fdefault = $v; break;
                case 'NOTNULL': $fnotnull = $v; break;
                case 'NOQUOTE': $fnoquote = $v; break;
                case 'DEFDATE': $fdefdate = $v; break;
                case 'DEFTIMESTAMP': $fdefts = $v; break;
                case 'CONSTRAINT': $fconstraint = $v; break;
                // let INDEX keyword create a 'very standard' index on column
                case 'INDEX': $findex = $v; break;
                case 'UNIQUE': $funiqueindex = true; break;
                } //switch
            } // foreach $fld

            //--------------------
            // VALIDATE FIELD INFO
            if (!strlen($fname)) {
                if ($this->debug) ADOConnection::outp("Undefined NAME");
                return false;
            }

            $fid = strtoupper(preg_replace('/^`(.+)`$/', '$1', $fname));
            $fname = $this->NameQuote($fname);

            if (!strlen($ftype)) {
                if ($this->debug) ADOConnection::outp("Undefined TYPE for field '$fname'");
                return false;
            } else {
                $ftype = strtoupper($ftype);
            }

            $ftype = $this->_GetSize($ftype, $ty, $fsize, $fprec);

            if ($ty == 'X' || $ty == 'X2' || $ty == 'B') $fnotnull = false; // some blob types do not accept nulls

            if ($fprimary) $pkey[] = $fname;

            // some databases do not allow blobs to have defaults
            if ($ty == 'X') $fdefault = false;

            // build list of indexes
            if ($findex != '') {
                if (array_key_exists($findex, $idxs)) {
                    $idxs[$findex]['cols'][] = ($fname);
                    if (in_array('UNIQUE', $idxs[$findex]['opts']) != $funiqueindex) {
                        if ($this->debug) ADOConnection::outp("Index $findex defined once UNIQUE and once not");
                    }
                    if ($funiqueindex && !in_array('UNIQUE', $idxs[$findex]['opts']))
                        $idxs[$findex]['opts'][] = 'UNIQUE';
                }
                else
                {
                    $idxs[$findex] = array();
                    $idxs[$findex]['cols'] = array($fname);
                    if ($funiqueindex)
                        $idxs[$findex]['opts'] = array('UNIQUE');
                    else
                        $idxs[$findex]['opts'] = array();
                }
            }

            //--------------------
            // CONSTRUCT FIELD SQL
            if ($fdefts) {
                if (substr($this->connection->databaseType,0,5) == 'mysql') {
                    $ftype = 'TIMESTAMP';
                } else {
                    $fdefault = $this->connection->sysTimeStamp;
                }
            } else if ($fdefdate) {
                if (substr($this->connection->databaseType,0,5) == 'mysql') {
                    $ftype = 'TIMESTAMP';
                } else {
                    $fdefault = $this->connection->sysDate;
                }
            } else if ($fdefault !== false && !$fnoquote) {
                if ($ty == 'C' or $ty == 'X' or
                    ( substr($fdefault,0,1) != "'" && !is_numeric($fdefault))) {

                    if (($ty == 'D' || $ty == 'T') && strtolower($fdefault) != 'null') {
                        // convert default date into database-aware code
                        if ($ty == 'T')
                        {
                            $fdefault = $this->connection->DBTimeStamp($fdefault);
                        }
                        else
                        {
                            $fdefault = $this->connection->DBDate($fdefault);
                        }
                    }
                    else
                    if (strlen($fdefault) != 1 && substr($fdefault,0,1) == ' ' && substr($fdefault,strlen($fdefault)-1) == ' ')
                        $fdefault = trim($fdefault);
                    else if (strtolower($fdefault) != 'null')
                        $fdefault = $this->connection->qstr($fdefault);
                }
            }
            $suffix = $this->_CreateSuffix($fname,$ftype,$fnotnull,$fdefault,$fautoinc,$fconstraint,$funsigned);

            // add index creation
            if ($widespacing) $fname = str_pad($fname,24);

             // check for field names appearing twice
            if (array_key_exists($fid, $lines)) {
                 ADOConnection::outp("Field '$fname' defined twice");
            }

            $lines[$fid] = $fname.' '.$ftype.$suffix;

            if ($fautoinc) $this->autoIncrement = true;
        } // foreach $flds

        return array($lines,$pkey,$idxs);
    }

    function _GetSize($ftype, $ty, $fsize, $fprec)
    {
        if (strlen($fsize) && $ty != 'X' && $ty != 'B' && strpos($ftype,'(') === false) {
            $ftype .= "(".$fsize;
            if (strlen($fprec)) $ftype .= ",".$fprec;
            $ftype .= ')';
        }
        return $ftype;
    }


    // return string must begin with space
    function _CreateSuffix($fname,&$ftype,$fnotnull,$fdefault,$fautoinc,$fconstraint,$funsigned)
    {
        $suffix = '';
        if (strlen($fdefault)) $suffix .= " DEFAULT $fdefault";
        if ($fnotnull) $suffix .= ' NOT NULL';
        if ($fconstraint) $suffix .= ' '.$fconstraint;
        return $suffix;
    }

    function _IndexSQL($idxname, $tabname, $flds, $idxoptions)
    {
        $sql = array();

        if ( isset($idxoptions['REPLACE']) || isset($idxoptions['DROP']) ) {
            $sql[] = sprintf ($this->dropIndex, $idxname);
            if ( isset($idxoptions['DROP']) )
                return $sql;
        }

        if ( empty ($flds) ) {
            return $sql;
        }

        $unique = isset($idxoptions['UNIQUE']) ? ' UNIQUE' : '';

        $s = 'CREATE' . $unique . ' INDEX ' . $idxname . ' ON ' . $tabname . ' ';

        if ( isset($idxoptions[$this->upperName]) )
            $s .= $idxoptions[$this->upperName];

        if ( is_array($flds) )
            $flds = implode(', ',$flds);
        $s .= '(' . $flds . ')';
        $sql[] = $s;

        return $sql;
    }

    function _DropAutoIncrement($tabname)
    {
        return false;
    }

    function _TableSQL($tabname,$lines,$pkey,$tableoptions)
    {
        $sql = array();

        if (isset($tableoptions['REPLACE']) || isset ($tableoptions['DROP'])) {
            $sql[] = sprintf($this->dropTable,$tabname);
            if ($this->autoIncrement) {
                $sInc = $this->_DropAutoIncrement($tabname);
                if ($sInc) $sql[] = $sInc;
            }
            if ( isset ($tableoptions['DROP']) ) {
                return $sql;
            }
        }
        $s = "CREATE TABLE $tabname (\n";
        $s .= implode(",\n", $lines);
        if (sizeof($pkey)>0) {
            $s .= ",\n                 PRIMARY KEY (";
            $s .= implode(", ",$pkey).")";
        }
        if (isset($tableoptions['CONSTRAINTS']))
            $s .= "\n".$tableoptions['CONSTRAINTS'];

        if (isset($tableoptions[$this->upperName.'_CONSTRAINTS']))
            $s .= "\n".$tableoptions[$this->upperName.'_CONSTRAINTS'];

        $s .= "\n)";
        if (isset($tableoptions[$this->upperName])) $s .= $tableoptions[$this->upperName];
        $sql[] = $s;

        return $sql;
    }

    function _Triggers($tabname,$taboptions)
    {
        return array();
    }

    function _Options($opts)
    {
        if (!is_array($opts)) return array();
        $newopts = array();
        foreach($opts as $k => $v) {
            if (is_numeric($k)) $newopts[strtoupper($v)] = $v;
            else $newopts[strtoupper($k)] = $v;
        }
        return $newopts;
    }


    function _getSizePrec($size)
    {
        $fsize = false;
        $fprec = false;
        $dotat = strpos($size,'.');
        if ($dotat === false) $dotat = strpos($size,',');
        if ($dotat === false) $fsize = $size;
        else {
            $fsize = substr($size,0,$dotat);
            $fprec = substr($size,$dotat+1);
        }
        return array($fsize, $fprec);
    }

    function ChangeTableSQL($tablename, $flds, $tableoptions = false, $dropOldFlds=false)
    {
    global $ADODB_FETCH_MODE;

        $save = $ADODB_FETCH_MODE;
        $ADODB_FETCH_MODE = ADODB_FETCH_ASSOC;
        if ($this->connection->fetchMode !== false) $savem = $this->connection->SetFetchMode(false);

        // check table exists
        $save_handler = $this->connection->raiseErrorFn;
        $this->connection->raiseErrorFn = '';
        $cols = $this->MetaColumns($tablename);
        $this->connection->raiseErrorFn = $save_handler;

        if (isset($savem)) $this->connection->SetFetchMode($savem);
        $ADODB_FETCH_MODE = $save;

        if ( empty($cols)) {
            return $this->CreateTableSQL($tablename, $flds, $tableoptions);
        }

        if (is_array($flds)) {
        // Cycle through the update fields, comparing
        // existing fields to fields to update.
        // if the Metatype and size is exactly the
        // same, ignore - by Mark Newham
            $holdflds = array();
            foreach($flds as $k=>$v) {
                if ( isset($cols[$k]) && is_object($cols[$k]) ) {
                    // If already not allowing nulls, then don't change
                    $obj = $cols[$k];
                    if (isset($obj->not_null) && $obj->not_null)
                        $v = str_replace('NOT NULL','',$v);
                    if (isset($obj->auto_increment) && $obj->auto_increment && empty($v['AUTOINCREMENT']))
                        $v = str_replace('AUTOINCREMENT','',$v);

                    $c = $cols[$k];
                    $ml = $c->max_length;
                    $mt = $this->MetaType($c->type,$ml);

                    if (isset($c->scale)) $sc = $c->scale;
                    else $sc = 99; // always force change if scale not known.

                    if ($sc == -1) $sc = false;
                    list($fsize, $fprec) = $this->_getSizePrec($v['SIZE']);

                    if ($ml == -1) $ml = '';
                    if ($mt == 'X') $ml = $v['SIZE'];
                    if (($mt != $v['TYPE']) || ($ml != $fsize || $sc != $fprec) || (isset($v['AUTOINCREMENT']) && $v['AUTOINCREMENT'] != $obj->auto_increment)) {
                        $holdflds[$k] = $v;
                    }
                } else {
                    $holdflds[$k] = $v;
                }
            }
            $flds = $holdflds;
        }


        // already exists, alter table instead
        list($lines,$pkey,$idxs) = $this->_GenFields($flds);
        // genfields can return FALSE at times
        if ($lines == null) $lines = array();
        $alter = 'ALTER TABLE ' . $this->TableName($tablename);
        $sql = array();

        foreach ( $lines as $id => $v ) {
            if ( isset($cols[$id]) && is_object($cols[$id]) ) {

                $flds = Lens_ParseArgs($v,',');

                //  We are trying to change the size of the field, if not allowed, simply ignore the request.
                // $flds[1] holds the type, $flds[2] holds the size -postnuke addition
                if ($flds && in_array(strtoupper(substr($flds[0][1],0,4)),$this->invalidResizeTypes4)
                 && (isset($flds[0][2]) && is_numeric($flds[0][2]))) {
                    if ($this->debug) ADOConnection::outp(sprintf("<h3>%s cannot be changed to %s currently</h3>", $flds[0][0], $flds[0][1]));
                    #echo "<h3>$this->alterCol cannot be changed to $flds currently</h3>";
                    continue;
                }
                $sql[] = $alter . $this->alterCol . ' ' . $v;
            } else {
                $sql[] = $alter . $this->addCol . ' ' . $v;
            }
        }

        if ($dropOldFlds) {
            foreach ( $cols as $id => $v )
                if ( !isset($lines[$id]) )
                    $sql[] = $alter . $this->dropCol . ' ' . $v->name;
        }
        return $sql;
    }
} // class