Document #
     Using RECALC in R:BASE 4.5
     PRODUCT:  R:BASE                  VERSION:  4.5
     AREA:  Entry/Exit Procedures      CATEGORY:  Programming in R:BASE
     In R:BASE 3.x-4.0, you used RECALC in an Entry/exit procedure (EEP)
     to force recalculation of form expressions that were dependent on the
     EEP field. R:BASE 4.5 has added two new RECALC options for use in
     RECALC VARIABLES - forces recalculation of all expressions defined
     for the current table and all located variables for that table.
     Expressions and variables for other tables are not affected.
     RECALC VARIABLES is usually used in a field level EEP.
     RECALC TABLES - forces recalculation of expressions and variables on
     all lower tables in the form. A RECALC TABLES in an EEP on table 2
     of the form, for example, recalculates tables 3, 4 and 5. RECALC
     TABLES is usually used in a table level EEP.
     Here are examples using the new RECALC options.
     No more "No editable data"
     The RECALC TABLES gets rid of "no editable data" messages when
     editing data in multi-table forms. Lower tables may not yet have any
     matching data records with table one in the form. When the user moves
     to the lower table, they get a "No editable data in this table"
     message on line 24. A new row can be added using the Add row option
     off the Edit menu, but this is not intuitive to all users. Use an EEP
     placed at the table level, On exit from a row, to automatically add a
     row to the lower table if there is no matching data row already.
     Users will never again see the "No editable data" message.
     Using the Concomp sample database, modify the form custform. Add an
     expression to table one of the form, Customer, to place the custid
     value into a variable. The value needs to be placed in a variable so
     the EEP can reference it. Define vcustid = custid. The variable is
     not located.
     The EEP counts the number of rows in the Contact table, table two on
     the form, that have a matching custid value with the current row in
     the Customer table. If no matching rows are found, the EEP inserts
     a row into the Contact table and uses RECALC TABLES to ensure that the
     form displays that new row.
     Placing the EEP as a field level EEP executes only if that particular
     field is entered. A user can move between tables in a form from any
     field. Placing the EEP at the table level ensures that it will always
     The EEP is placed On exit from a row. Because it will execute anytime
     the user leaves the row, you must check for keystrokes. If the user
     presses Esc or moves to the menu using the Alt key you don't want to
     execute the commands in the EEP.
       adds a row of data to lower tables in a form)
     SET VAR vkey = (LASTKEY(0))
     IF vkey = '[Esc]' OR +
        vkey LIKE '[Alt]%' THEN
     SET VAR vcount INT
     SEL COUNT(*) INTO vcount +
       FROM contact WHERE custid=.vcustid
     IF vcount = 0 THEN
       INSERT INTO contact (custid) +
         VALUES (.vcustid)
     Summing rows in a region
     RECALC TABLES can also do summing in forms. Create a dummy table -
     CREATE TABLE DUMMY (col1 INTEGER) - and add one row of data to the
     dummy table. Add the dummy table to the form as a table after the
     region you want to sum. Locate a variable, vtotal, for the dummy
     table and define an expression for vtotal. The expression calculates
     the sum of the region rows. For example, to sum the rows for the
     Transdetail table on the form tranform, use this expression:
     vtotal =. (SUM(extprice)) +
                IN transdetail +
                WHERE transid = .vtransid
     Vtransid is a variable defined for table Transdetail on the form, the
     region table. It is simply vtransid = transid, and places the current
     column value into the variable for use by the dummy table expression.
     Then, on the region table, Transdetail, place an EEP to execute On
     entry into a row. The EEP has just one line in it, RECALC TABLES. As
     you enter each row in the region, the expression on the lower table
     (dummy table) is recalculated - the sum of the rows in the region
     Calculate and display many variables
     Use RECALC VARIABLES to display multiple lookup values on a form. You
     can replace many form expressions or even a whole table. For example,
     in the form tranform in the Concomp sample database, instead of
     placing the Customer table on the form, lookup the desired data values
     in an EEP and display them using RECALC VARIABLES. This makes tranform
     a two table form instead of a three table form and speeds it up.
     Define a form variable, vcustid = custid, for the Transmaster table.
     Modify the field settings for custid and specify a double column
     popup using the custid and company columns from the Customer table.
     This makes it easy to select the right customer. Add an Exit EEP on
     custid. The EEP will lookup the rest of the customer information and
     display it.
     The EEP uses a single SELECT command to lookup all the values at
     once. Then the RECALC VARIABLES tells the form to redisplay all
     located variables and all defined expressions for the Transmaster
       Field level EEP to lookup up customer data)
     SELECT company, custaddress, +
     (custcity + ',' & custstate & custzip), +
     custphone INTO +
     vcompany ind1, vaddr ind2, vcsz ind3, +
     vphone ind4 +
     FROM customer WHERE custid=.vcustid
     Be sure to locate the variables on the form using the same names as
     used in the EEP. If the names are different, the new values won't
     display on the form. Because the values are now variables instead of
     columns, they retain their value from row to row unless reset. Use a
     table level EEP on Transmaster, After saving row, to reset the
     variables to NULL. It is important to just reset the variables to NULL
     and not clear them using the CLEAR VAR command. Clearing located
     variables can cause the form to not work correctly.
     The EEP to reset the variables to NULL needs just a single SET VAR
       reset located variables to NULL)
     SET VAR vcompany=NULL, vcompany=NULL, +
     vaddr=NULL, vcsz=NULL, vphone=NULL
     This procedure works well for non-editable fields. You are no longer
     limited to looking up or calculating variables one at a time. Now you
     can have a single EEP do all the calculations and lookups needed for
     the table. This provides for easier maintenance of the form and
     better performance.