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An alias creates a second reference for a table without duplicating the file on disk. You can add an alias for a table only if it is already on the Dictionary list.
General
Name | Type a data table “name”, as you wish to refer to it in your code. The name must be a valid Clarion label. |
Description | Enter a string description for the alias. Clarion displays the descriptions in dialogs such as the Dictionary dialog. |
Prefix | By default, Clarion will use the first three letters of the Name for the prefix. Optionally specify up to 14 characters to use as a Prefix. |
Alias Table | Choose a table from the drop down list. This is the original table that the alias “references.” The drop down list shows only the tables previously defined using the Add Table command in thesoftvelocity datadictionary editor dictionaryeditor.htmDictionary Properties dialog. |
Comments
Allows you to enter a text description describing the alias. The description is solely for your convenience, and has no effect on the application. It is useful for situations in which other programmers may pick up your code later, or for when you expect to return to the project after a long period of time since you last looked at it.
Options
Do Not Auto-Populate This Aliased Table
Directs the wizards to skip the Aliased Table when creating primary Browse procedures or Report procedures.
User Options User Options are provided to enable you to provide information to be used by a third-party template set. User Options are comma delimited, that is, each entry is separated by a comma.
Follow the instructions provided with your add-on template set.
See Also: Using Wizard Options
A table alias provides several advantages, at the cost of some system overhead:
It allows you to set multiple relationships between tables.
Strict relational database theoreticians state a table may only have a single relational link to another table at a time. Aliases allow you to “legally” work around this limitation. See Also: How to Design Your Dictionary and Database
It allows a second table buffer for the same table.
You could use this for a second table browse, as well as entry forms and other items for each. This is particularly useful for an MDI application.
On the negative side, the second table buffer takes up additional memory and resources.
Any table driver utilizing external key files requires additional file handles for each alias. For example, a table with three external keys and three aliases requires sixteen file handles: one each for the “first” data table and its three keys, and an additional four for each of the aliases. When using aliases, we recommend choosing a database driver that stores keys internally, such as TopSpeed or Btrieve.
When using aliases, you must open the table in Share mode.
To modify the alias properties at a later time, highlight the table name on the Dictionary dialog list, then either double-click or press the Properties button.
You can edit the columns and keys for the Alias by pressing the Columns/Keys button. The Columns/Key Definition dialog lists the columns and keys for the original table; any changes you make will update the originals.