Determining Current Block and Current Item in Oracle Forms

最新推荐文章于 2025-09-11 20:53:34 发布

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#数据库

本文介绍了Oracle Forms中用于确定当前导航单元的系统变量SYSTEM.CURSOR_BLOCK和SYSTEM.CURSOR_ITEM。通过具体示例展示了如何使用这些变量来实现不同块间的导航及获取焦点所在项。

SYSTEM.CURSOR_BLOCK

Determining current block in Oracle Forms Using SYSTEM.CURSOR_BLOCK system variable. The value that the SYSTEM.CURSOR_BLOCK system variable represents depends on the current

navigation unit:
If the current navigation unit is the block, record, or item (as in the Pre- and Post- Item, Record, and Block triggers), the value of SYSTEM.CURSOR_BLOCK is the name of the block where the cursor is located. The value is always a character string. If the current navigation unit is the form (as in the Pre- and Post-Form triggers), the value of SYSTEM.CURSOR_BLOCK is NULL.

SYSTEM.CURSOR_BLOCK examples

Assume that you want to create a Key-NXTBLK trigger at the form level that navigates depending on what the current block is. The following trigger performs this function, using :SYSTEM.CURSOR_BLOCK stored in a local variable.

DECLARE
curblk VARCHAR2(30);
BEGIN
curblk := :System.Cursor_Block;
IF curblk = ’ORDERS’
THEN Go_Block(’ITEMS’);
ELSIF curblk = ’ITEMS’
THEN Go_Block(’CUSTOMERS’);
ELSIF curblk = ’CUSTOMERS’
THEN Go_Block(’ORDERS’);
END IF;
END;

SYSTEM.CURSOR_ITEM

Determining current item using System.Cursor_Item in Oracle Forms. SYSTEM.CURSOR_ITEM represents the name of the block and item, block.item, where the input focus (cursor) is located.The value is always a character string.

Usage Notes

Within a given trigger, the value of SYSTEM.CURSOR_ITEM changes when navigation takes place. This differs from SYSTEM.TRIGGER_ITEM, which remains the same from the beginning to the end of single trigger.

SYSTEM.CURSOR_ITEM examples

Assume that you want to create a user-defined procedure that takes the value of the item where the cursor is located (represented by SYSTEM.CURSOR_VALUE), then multiplies the value by a constant, and then reads the modified value into the same item. The following user-defined procedure uses the COPY built-in to perform this function.

PROCEDURE CALC_VALUE IS
new_value NUMBER;
BEGIN
new_value := TO_NUMBER(:System.Cursor_Value) * .06;
Copy(TO_CHAR(new_value), :System.Cursor_Item);
END;