WHERE-STRING attribute

Returns and allows you to modify the current WHERE expression from the query generated for a specified data-relation that links the child table to its parent.

Data type:

CHARACTER

Access:

Readable/Writeable

Applies to:

Data-relation object handle

This attribute evaluates to the WHERE expression from the query that the AVM generates for you based on the data-relation between parent and child buffers. You can also use this attribute to build an extended query of your own based on this default relationship.

Note:

You can provide the initial WHERE expression for a query using the FILL-WHERE-STRING attribute.

If you assign a new value to the attribute, the AVM uses the new WHERE expression when it re-opens the query during navigation to filter the child table of the data-relation. When you set this attribute, if the AVM finds an error in the new WHERE expression, it raises a run-time error on the assignment.

The NAME attribute of the Temp-table object handle is writeable for dynamic and AVM-generated temp-tables. You might need to update a WHERE-STRING that references a renamed temp-table with new strings using the new table name.

Typically, you modify an existing WHERE expression by appending additional conditions to it, as shown in the r-wherestr.p example procedure. This example provides the initial WHERE expression using the FILL-WHERE-STRING attribute. It then generates the complete initial query for the data-relation with the call to the ProDataSet FILL( ) method, and uses the WHERE-STRING attribute to modify the existing WHERE expression to further filter the query buffers.

 

r-wherestr.p

DEFINE TEMP-TABLE ttCus LIKE Customer. DEFINE TEMP-TABLE ttOrder LIKE Order. DEFINE DATASET dsCus FOR ttCus,ttOrder DATA-RELATION dr1   FOR ttCus, ttOrder RELATION-FIELDS(CustNum,CustNum).   DEFINE DATA-SOURCE dscCus FOR Customer. DEFINE DATA-SOURCE dscOrd FOR Order.   DEFINE QUERY q1 FOR ttCus. DEFINE QUERY q2 FOR ttOrder.   DEFINE BROWSE b1 QUERY q1   DISPLAY ttCus.CustNum ttCus.Name ttCus.Address WITH 3 DOWN. DEFINE BROWSE b2 QUERY q2   DISPLAY ttOrder.CustNum ttOrder.OrderNum ttOrder.ShipDate WITH 6 DOWN.   BUFFER ttCus:ATTACH-DATA-SOURCE(DATA-SOURCE dscCus:HANDLE). BUFFER ttOrder:ATTACH-DATA-SOURCE(DATA-SOURCE dscOrd:HANDLE). DATA-SOURCE dscCus:FILL-WHERE-STRING = "WHERE CustNum < 3". DATASET dsCus:FILL( ).   DATASET dsCus:GET-RELATION(1):WHERE-STRING   = DATASET dsCus:GET-RELATION(1):WHERE-STRING     + " AND ttOrder.OrderNum < 100".   /* Shows full dataset */ FOR EACH ttCus:   DISPLAY ttCus.CustNum.   FOR EACH ttOrder OF ttCus:     DISPLAY ttOrder.OrderNum ttOrder.OrderDate.   END. END.   BROWSE b1:QUERY = DATASET dsCus:TOP-NAV-QUERY. BROWSE b2:QUERY = DATASET dsCus:GET-RELATION(1):QUERY.   /* Shows only filtered records */ ENABLE b1 b2 WITH FRAME frX ROW 1 SIZE 70 BY 30.   WAIT-FOR WINDOW-CLOSE OF CURRENT-WINDOW.

See also:

FILL-WHERE-STRING attribute, QUERY attribute