Field Descriptors

Field Descriptors are an important and powerful part of WOW. A Field Descriptor describes a field within a

table or database. Field Descriptors contain information such as the external name of a field, whether or

not the field is required, and the type of data the field contains, such as numeric, time, etc. Utilizing Field

Descriptors allows WOW to perform validation, display formatting, and other tasks for your application

without any coding on your part.

Field Descriptors are attached to database fields by field name, table/file name, and WOW connection. You can have

multiple WOW applications that use the same field descriptors IF they use the same connection, library, and tables.

In this case, changing a field descriptor will affect multiple applications which can be a benefit.

Logical files/views can be used to enable independent field descriptors as well as derived field descriptors.

Optionally, field descriptors can be shared shared where the same tables exist in multiple libraries (see below).

Note: Field Descriptors should be created for all tables that WOW uses frequently. We encourage creating

Field Descriptors for all production level tables/environments.

Field Descriptor Manager

To edit or create Field Descriptors you first must be in the Field Descriptor Manager. The easiest way to get to

the Field Descriptor Manager is to click on the small "FD" icon above any results table or the gear icon on any column.

This will bring up the Field Descriptor Manager in a new window:

You can also start up Field Descriptor Manager from WOW directly without first running your application. Click on the Setup Connections link on the left side of the builder. You can then select a connection whose field descriptors you want to manage and click the Edit FDs field. Whenever you are using Field Descriptor Manager, you are managing the field descriptors for a single connection. To manage field descriptors for another connection, you must choose a different connection (or a table retrieved using that connection) and open up Field Descriptor Manager from that connection or table.

The "Enter library" and "Enter table" fields at the top of the main Field Descriptor Manager screen allow you to type in the name of the library and table whose Field Descriptors you want to work with or create. Alternatively, you can click one of the "Select from list" radio buttons and choose the library or table from the list of libraries or tables available (double click an entry in the list to select it) Once you have picked a library or table to work with, the following options are available:

Library Functions

• • Enter Library - This shows what library you are currently in. If you would like to change your current library click the radio button below and select the library in the list given. If a table’s FDs are shared, specify * for the library name.

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  • View FDs - Displays all of the Field Descriptors within the entire library. This may take some time to complete, depending on the number of tables in the library. It is usually better to display the Field Descriptors for a single table at a time.

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  • Create FDs - Creates Field Descriptors for the entire library. Creating Field Descriptors for the entire library is not recommended – it is usually better to create them separately for each table.

Table Functions

• • Enter Table - This shows you which table you are currently in. If you would like to switch your current table, click the radio button below and select the table you would like in the list given.

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  • View FDs - Displays all of the Field Descriptors already created for the table. In most cases the FDs are already displayed below, if for some reason the FDs are not displayed click this button and they will be displayed.

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  • Share FDs - Allows you to share the Field Descriptors for this table with other tables which have the same name, but are in different libraries. By default, a table’s Field Descriptors are only for that table, and not for any other tables, even if those tables have the same name. This function will not share Field Descriptors for multiple connections. Each connection holds a unique set of Field Descriptors. If a table’s FDs are shared, you must specify * for the library name. More Details.

  • Create FDs - Creates field descriptors for the currently selected table.

  • Reset FD Cache - For advanced users only. This button is used for troubleshooting purposes. Internally, WOW caches Field Descriptors as they are read – this button clears the cached FDs. This function can be helpful when FD changes recently made do not appear to be affecting the operations using this table and connection.

TAGS: field properties