JTable
From Joomla! Documentation
The "API15" namespace is an archived namespace. This page contains information for a Joomla! version which is no longer supported. It exists only as a historical reference, it will not be improved and its content may be incomplete and/or contain broken links.
JTable is an abstract class that forms the basis for all database table classes. Some of the methods listed will be overridden by the child class so you should check the child class documentation for further information.
Each physical database table created should have a corresponding class derived from JTable to represent it. JTable provides many methods to make common manipulations to the table much simpler. For example, one of the most common operations you will need to perform is to read a table row into memory given a value for the primary key. This can be done easily using the load method. The table row can then be just as easily updated using the save method, which also performs any predefined sanity checks on the table fields.
Defined in[edit]
libraries/joomla/database/table.php
Methods[edit]
| Method name | Description |
|---|---|
| __construct | Object constructor to set table and key field |
| getInstance | Returns a reference to the a Table object, always creating it |
| getDBO | Get the internal database object |
| setDBO | Set the internal database object |
| getTableName | Gets the internal table name for the object |
| getKeyName | Gets the internal primary key name |
| reset | Resets the default properties void |
| bind | Binds a named array/hash to this object |
| load | Loads a row from the database and binds the fields to the object properties |
| check | Generic check method |
| store | Inserts a new row if id is zero or updates an existing row in the database table |
| move | Description |
| getNextOrder | Returns the ordering value to place a new item last in its group |
| reorder | Compacts the ordering sequence of the selected records |
| canDelete | Generic check for whether dependancies exist for this object in the db schema |
| delete | Default delete method |
| checkout | Checks out a row |
| checkin | Checks in a row |
| hit | Description |
| save | Generic save function |
| publish | Generic Publish/Unpublish function |
| toXML | Export item list to xml |
| addIncludePath | Add a directory where JTable should search for table types. You may either pass a string or an array of directories. |
| isCheckedOut | Check if an item is checked out |
Importing[edit]
jimport( 'joomla.database.table' );
Examples[edit]
Code Examples[edit]
Automatically Generated Properties
As of Joomla 2.5, JTable properties are automatically generated based on the schema of the specified table. When you specify a table in a class that extends JTable, the field names are read from the table and set as properties. When using Joomla 1.5, you must manually declare all table columns as properties of the class that extends JTable.
Reserved Database Field Names
Some of the optional features of JTable require the existence of specially-named fields in the database table. If you require this additional functionality you should ensure that these named fields are present in the table. These field names should be considered reserved as any attempts to use them for purposes other than those supported by JTable may result in conflict.
| Field name | Methods using the field name |
|---|---|
| checked_out | checkOut, checkIn, isCheckedOut |
| checked_out_time | checkOut, checkIn, isCheckedOut |
| hits | hit |
| ordering | getNextOrder, reorder, move |
| published | publish |
Check-in/check-out
Joomla tables implement a simple mechanism for preventing a race condition while editing rows in a database. This depends on the existence of database fields called "checked_out" and "checked_out_time" and if these fields are present JTable will automatically support this mechanism so that it can be easily used in your tables too. In addition to the checkOut and checkIn methods, there is a isCheckedOut method to determine if a given table row is currently checked out by another user.
Hit counter
Some Joomla tables contain a field called "hits" which records the number of times that a table row has been accessed. JTable provides a simple method to increment this field: hit.