The DataGrid Class and Sorting by Columns
Table, is great for drawing basic HTML tables, but can overload a web page
when trying to display a large amount of information.
The DataGrid class is a subclass of Table and has features that allow the table
to be a view into a larger set of data that is stored in a database, without rendering all the data. The effect
gives the user fast access to large amounts of data.
One feature of DataGrid is it allows you to click on column headers to sort the data in the table.
Sorting is provided by SQL, and each click causes the database to be queried with a sort clause corresponding to the
column that was clicked.
To enable this, you add the properties OrderByClause and ReverseOrderByClause to each column.
(It is possible
to also just define OrderByClause, and to leave ReverseOrderByClause undefined). The QQ Clause
you specify is given back to you when you call the OrderByClause property on the DataGrid
when you query the database in the data binder. You then pass this clause to your class's loadAll() or loadArrayBy...()
method as one of the optional QQ Clause parameters. Note that all QCubed code generated loadAll() and loadArrayBy...()
methods take in an optional $objOptionalClauses parameter which conveniently uses the clause returned by the DataGrid's
Convenient how they end up working together, isn't it? =)
Click on the column headers in the table to see the sorting in action.