HOWTO: Set a Primary Key to Updateable in a View

By default, when creating a view on a table, any field with a primary key index is not marked as updateable. This article illustrates how you can mark the primary key as updateable through the View Designer, and programmatically.

View Designer

To mark the primary key as updateable through the View Designer interface, use the following steps:

1. Open the view in the View Designer.
2. Click the Update Criteria tab.
3. Click the Update column beside the primary key field.
   
   NOTE: The Update column has a column header that looks like a pencil. If you do not select the Update column and you attempt to INSERT a new record, you may receive one of the following errors:
   Connectivity error: [Microsoft][ODBC Visual FoxPro Driver Field <fieldname> does not accept null values.
   -or-
   Mandatory not null field - missing or null during insert.

Programmatically

To mark the primary key as updateable programmatically, use the following steps:

1. Open the Tastrade database in the VFP\Samples\Tastrade\Data folder in Visual FoxPro 5.0, or the home(2)+"Tastrade\Data" folder in Visual FoxPro 6.0.
2. Run the following program to create a new SQL view based on the Customer table.

         ***********RunFirst.prg***********
         CREATE SQL VIEW MYTEST AS SELECT * FROM CUSTOMER
         DBSETPROP("MYTEST","VIEW","SENDUPDATES",.T.)
         ***********End RunFirst.prg*************
   							

3. Modify the view in the View Designer and note that the primary key is not marked for updates.
4. Create a program called MarkPrimary and place the following code in it:

         ************MarkPrimary.prg****************
         PARAMETERS ViewName
   
         x=ALIAS()
         USE IN 0 &viewname
         PrimKeys = CURSORGETPROP('KeyFieldList',viewname)
         i=1
         remField=PrimKeys
         DO WHILE i <> 0
            nextcomma=AT(remField,",")
            IF nextcomma=0 and len(remfield)=0 THEN
               i=0
               EXIT
            ELSE
               IF nextcomma=0 and LEN(remfield)<>0 then
                  tmpfield=remfield
                  y= DBSETPROP(ViewName + "." + ;
                  tmpField,'Field','UPDATABLE',.T.)
                  i=0
                  EXIT
               ELSE
                  tmpField=SUBSTR(remField,i,NextComma -1)
                  remfield=SUBSTR(remfield,nextcomma + 1)
                  i=nextcomma
                  y= DBSETPROP(ViewName + "." + ;
                  tmpField,'Field','UPDATABLE',.T.)
               ENDIF
            ENDIF
         ENDDO
   
         SELECT  (viewname)
         USE
         IF NOT EMPTY(x) THEN
            SELECT  (x)
         ENDIF
         **************End MarkPrimary.prg*******************
   							

5. Run the MarkPrimary.prg code by typing the following into the Command window:

         DO MARKPRIMARY WITH "MYTEST"
   							

6. Modify the view MyTest in the View Designer and notice that the primary key field is now marked for updates.