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TheApplicationOfTheInitialValueInForms6i

原创 Oracle 作者:YoungEric 时间:2009-06-15 09:42:24 0 删除 编辑

TheApplicationOfTheInitialValueInForms6i

--Eric, Jun 14, 2009

This chapter introduces the application of the initial vaule in Oracle Forms 6i.

SYSTEM.RECORD_STATUS

SYSTEM.RECORD_STATUS represents the status of the record where the cursor is located. The value can be one of four character strings:

Value Definition

CHANGED Indicates that a queried record's validation status is Changed.

INSERT Indicates that the record's validation status is Changed and that the record does not exist in the database.

NEW Indicates that the record's validation status is New.

QUERY Indicates that the record's validation status is Valid and that it was retrieved from the database.

DATA BLOCK

Data blocks are associated with data (table columns) within a database.

By default, the association between a data block and the database allows operators to automatically query, update, insert, and delete rows within a database.

Data blocks can be based on database tables, views, procedures, or transactional triggers.

CONTROL BLOCK

In contrast, a control block is not associated with the database, and the items in a control block do not relate to table columns within a database.

INITIAL VALUES

The default value of an item is determined by the value of the Initial Value item property. Form Builder assigns a default value to an item when a new record is created. Specifically, Form Builder assigns the default value whenever the item is part of a record whose status is marked NEW.

INITIAL VALUES BE VALID

  1. When Form Builder creates a null record in the block, the status of the null record is NEW. The initial value set by the initial value property will be valid.
  2. If you initials an item in the PRE-FORM trigger,the initial value will be valid.

INITIAL VALUES BE INVALID

When Form Builder creates a null record in the block, the status of the null record is NEW.Before you use GO_BLOCK to navigate to the indicated block, if you assign any one item of the indicated data or control block by “:block_name.item_name := item_value”, the initial value set by the initial value property will be invalid.Because the status of the record is changed into INSERT,not NEW.

Form Builder assigns the default value whenever the item is part of a record whose status is marked NEW,not other record status.

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