Class TMssqlCommandBuilder

TComponent
   |
   --TDbCommandBuilder
      |
      --TMssqlCommandBuilder

TMssqlCommandBuilder provides specifics methods to create limit/offset query commands for MSSQL servers.

Method Summary
string	applyLimitOffset ( string $sql, integer $limit, integer $offset) Overrides parent implementation. Alters the sql to apply $limit and $offset.
protected array	findOrdering ( string $sql) Base on simplified syntax http://msdn2.microsoft.com/en-us/library/aa259187(SQL.80).aspx
integer	getLastInsertID () Overrides parent implementation. Uses "SELECT @@Identity".
protected string	joinOrdering ( array $orders)
protected array	reverseDirection ( array $orders)
protected sql	rewriteLimitOffsetSql ( string $sql, integer $limit, integer $offset) Rewrite sql to apply $limit > and $offset > 0 for MSSQL database.

Methods Inherited From TDbCommandBuilder

TDbCommandBuilder::applyCriterias(), TDbCommandBuilder::applyLimitOffset(), TDbCommandBuilder::applyOrdering(), TDbCommandBuilder::bindArrayValues(), TDbCommandBuilder::bindColumnValues(), TDbCommandBuilder::createCommand(), TDbCommandBuilder::createCountCommand(), TDbCommandBuilder::createDeleteCommand(), TDbCommandBuilder::createFindCommand(), TDbCommandBuilder::createInsertCommand(), TDbCommandBuilder::createUpdateCommand(), TDbCommandBuilder::getColumnBindings(), TDbCommandBuilder::getDbConnection(), TDbCommandBuilder::getInsertFieldBindings(), TDbCommandBuilder::getLastInsertID(), TDbCommandBuilder::getPdoType(), TDbCommandBuilder::getSearchCondition(), TDbCommandBuilder::getSearchExpression(), TDbCommandBuilder::getTableInfo(), TDbCommandBuilder::hasIntegerKey(), TDbCommandBuilder::setDbConnection(), TDbCommandBuilder::setTableInfo()

Methods Inherited From TComponent

TComponent::addParsedObject(), TComponent::attachEventHandler(), TComponent::canGetProperty(), TComponent::canSetProperty(), TComponent::createdOnTemplate(), TComponent::detachEventHandler(), TComponent::evaluateExpression(), TComponent::evaluateStatements(), TComponent::getEventHandlers(), TComponent::getSubProperty(), TComponent::hasEvent(), TComponent::hasEventHandler(), TComponent::hasProperty(), TComponent::raiseEvent(), TComponent::setSubProperty(), TComponent::__get(), TComponent::__set()

Method Details

applyLimitOffset

public string applyLimitOffset

(string $sql , integer $limit , integer $offset )

Overrides parent implementation. Alters the sql to apply $limit and $offset.

The idea for limit with offset is done by modifying the sql on the fly with numerous assumptions on the structure of the sql string. The modification is done with reference to the notes from http://troels.arvin.dk/db/rdbms/#select-limit-offset

 SELECT * FROM (
  SELECT TOP n * FROM (
    SELECT TOP z columns      -- (z=n+skip)
    FROM tablename
    ORDER BY key ASC
  ) AS FOO ORDER BY key DESC -- ('FOO' may be anything)
 ) AS BAR ORDER BY key ASC    -- ('BAR' may be anything)

Regular expressions are used to alter the SQL query. The resulting SQL query may be malformed for complex queries. The following restrictions apply

Input
string	$sql	SQL query string.
integer	$limit	maximum number of rows, -1 to ignore limit.
integer	$offset	row offset, -1 to ignore offset.
Output
string	SQL with limit and offset.
Exception

findOrdering

protected array findOrdering

(string $sql )

Base on simplified syntax http://msdn2.microsoft.com/en-us/library/aa259187(SQL.80).aspx

Input
string	$sql
Output
array	ordering expression as key and ordering direction as value
Exception

getLastInsertID

public integer getLastInsertID

()

Overrides parent implementation. Uses "SELECT @@Identity".

Output
integer	last insert id, null if none is found.
Exception

joinOrdering

protected string joinOrdering

(array $orders )

Input
array	$orders	ordering obtained from findOrdering()
Output
string	concat the orderings
Exception

reverseDirection

protected array reverseDirection

(array $orders )

Input
array	$orders	original ordering
Output
array	ordering with reversed direction.
Exception

rewriteLimitOffsetSql

protected sql rewriteLimitOffsetSql

(string $sql , integer $limit , integer $offset )

Rewrite sql to apply $limit > and $offset > 0 for MSSQL database.

See http://troels.arvin.dk/db/rdbms/#select-limit-offset

Input
string	$sql	sql query
integer	$limit	> 0
integer	$offset	> 0
Output
sql	modified sql query applied with limit and offset.
Exception