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begin work merging Jacob's query parser
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git-svn-id: http://svn.php.net/repository/pear/packages/DBA_Relational/trunk@111624 c90b9560-bf6c-de11-be94-00142212c4b1
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Brent Cook committed Jan 13, 2003
1 parent 0ff1002 commit 9d839e7
Showing 1 changed file with 133 additions and 25 deletions.
158 changes: 133 additions & 25 deletions Relational.php
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Original file line number Diff line number Diff line change
Expand Up @@ -17,12 +17,16 @@
// | License along with this library; if not, write to the Free Software |
// | Foundation, Inc., 59 Temple Place, Suite 330,Boston,MA 02111-1307 USA|
// +----------------------------------------------------------------------+
// | Authors: Brent Cook <busterb@mail.utexas.edu> |
// | Jacob Lee <jacobswell4u@yahoo.com> |
// +----------------------------------------------------------------------+
//
// $Id$

require_once 'PEAR.php';
require_once 'DBA/Table.php';
require_once 'DBA/TempTable.php';
require_once 'SQL/Lexer.php';

/**
* A relational database manager using DBA_Table as a storage object.
Expand Down Expand Up @@ -58,6 +62,14 @@ class DBA_Relational extends PEAR
* @var string
*/
var $_driver;

/**
* Table of functions recognized in select/join parsing
* @access private
* @var array
*/
var $_functions;

// }}}

// {{{ DBA_Relational($home = '', $driver = 'file')
Expand All @@ -80,6 +92,10 @@ function DBA_Relational($home = '', $driver = 'file')

$this->_driver = $driver;

// we store symbols this way to take advantage of PHP's hash table
// implementation of associative arrays
$this->_functions = array_flip(get_class_methods('DBA_Functions'));

// create the _tables table. this keeps track of the tables to be used
// in DBA_Relational as well as which driver to use for each.
if (!$this->tableExists('_tables')) {
Expand Down Expand Up @@ -229,6 +245,7 @@ function dropTable($tableName, $driver=null)

return DBA::drop($tableName, $driver);
}
// }}}

// {{{ getSchema
/**
Expand Down Expand Up @@ -384,31 +401,6 @@ function fetch($tableName, $key)
}
// }}}

// {{{ select($tableName, $query, $rows=null)
/**
* Performs a select on a table. This means that a subset of rows in a
* table are filtered and returned based on the query. Accepts any valid
* expression of the form '(field == field) || (field > 3)', etc. Using the
* expression '*' returns the entire table
* SQL analog: 'select * from rows where rawQuery'
*
* @access public
* @param string $tableName table on which to operate
* @param string $rawQuery query expression for performing the select
* @param array $rows rows to select on
* @return mixed PEAR_Error on failure, the row array on success
*/
function select($tableName, $query, $rows=null)
{
$result = $this->_openTable($tableName, 'r');
if (PEAR::isError($result)) {
return $result;
} else {
return $this->_tables[$tableName]->select($query, $rows);
}
}
// }}}

// {{{ sort($fields, $order='a', $rows)
/**
* Sorts rows by field in either ascending or descending order
Expand Down Expand Up @@ -519,6 +511,122 @@ function _validateTable(&$table, &$rows, &$fields, $altName)
}
// }}}

// {{{ function _parseQuery($rawQuery)
function _parseQuery($rawQuery)
{
$PHPQuery = '';
$lexer = new Lexer($rawQuery,1);
$lexer->symbols = array('and'=>1, 'or'=>1);
$token = $lexer->lex();
while(!is_null($token)) {
switch($token) {
case 'and':
case 'or':
$PHPQuery .= ' '.$lexer->tokText.' ';
break;
case 'ident':
$token = strtolower($lexer->tokText);
if (isset($this->_functions[$token]) {
$PHPQuery .= 'DBA_Functions::'.$token;
} elseif (function_exists($lexer->tokText)) {
$PHPQuery .= $lexer->tokText;
} else {
$prevText = $lexer->tokText;
$token = $lexer->lex();
if ($token == '.') {
$token = $lexer->lex();
if ($token == 'ident') {
$PHPQuery .= '$row[\''.
$prevText.'.'.$lexer->tokText.'\']';
} else {
return $this->raiseError(
"invalid token. need field token");
}
} else {
$PHPQuery .= '$row["'.$prevText.'"]';
$lexer->pushBack();
}
}
break;
case 'text_val':
$PHPQuery .= '"'.$lexer->tokText.'"';
break;
case 'real_val':
case 'int_val':
default :
$PHPQuery .= $lexer->tokText;
break;
}
$token = $lexer->lex();
}
return $PHPQuery;
}
// }}}

// {{{ select($tableName, $query, $rows=null)
/**
* Performs a select on a table. This means that a subset of rows in a
* table are filtered and returned based on the query. Accepts any valid
* expression of the form '(field == field) || (field > 3)', etc. Using the
* expression '*' returns the entire table
* SQL analog: 'select * from rows where rawQuery'
*
* @access public
* @param string $tableName table on which to operate
* @param string $rawQuery query expression for performing the select
* @param array $rows rows to select on
* @return mixed PEAR_Error on failure, the row array on success
*/
/*
function select($tableName, $query, $rows=null)
{
$result = $this->_openTable($tableName, 'r');
if (PEAR::isError($result)) {
return $result;
} else {
return $this->_tables[$tableName]->select($query, $rows);
}
}
*/
// }}}

function select($tableName, $query, $rows=null)
{
$tables = $this->_parseTableString($tableName);

$result = $this->_openTable($tables['name'][0],'r');
if (PEAR::isError($result))
return $result;
$rows = $this->_tables[$tables['name'][0]]->getRows();
if ($tables['name'][0] == $tables['alias'][0])
$tables['alias'][0] = '';
$tblObject = new DBA_TempTable(&$rows, $tables['alias'][0]);

if (strlen($query)) {
if ($query == '*') {
$PHPQuery = true;
} else {
$PHPQuery = $this->_parseQuery($query);
}
} else {
$PHPQuery = true;
}

$rows = array();

$key = $tblObject->firstRow();
while ($key !== false) {
$row = $tblObject->getRow($key);
@eval('$isMatch = ('.$PHPQuery.') ? 1:0;');
if ($isMatch)
$rows[] = $row;
$key = $tblObject->nextRow();
}

return $rows;
}
// }}}

// {{{ _parsePHPQuery($rawQuery, $fieldsA, $fieldsB, $tableA, $tableB)
/**
* Constructs a PHP query based on $rawQuery
Expand Down

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