PRB: TYPE Function Does Not Indicate Character(Binary)

• Microsoft Visual FoxPro for Windows, version 5.0

SYMPTOMS

The TYPE() function does not differentiate between Character and Character(binary) or Memo and Memo(binary) field types. The Type() function simply returns a "C" or an "M," respectively.

WORKAROUND

Use the AFIELDS() function to create an array that contains information on each field in the table. The procedure listed below, bin_fld, contains code that determines whether a character or memo field is binary. Before executing this code, issue the CREATE TABLE syntax provided in step 1 of the "Steps To Reproduce Behavior" section below.

1. Create a program called Test that contains the following code:

   **** Begin Program Example **** PROC bin_fld PARAMETER a IF TYPE(a)= "C" OR TYPE(a) ="M"

            =AFIELDS(test)
            IF ASCAN(test,UPPER(a)) > 0
               fldtype=ASCAN(test,UPPER(a))+1
                  IF test(ASCAN(test,UPPER(a))+5)=.T.
                     retvalu= "Field Type: "+ test[fldtype]+ " Binary"
                  ELSE
                     retvalu= "Field Type: "+ test[fldtype]+ ' Not Binary'
                  ENDIF
            ENDIF
      ELSE
            retvalu= TYPE(a)
      ENDIF
      RETURN retvalu
      **** End program example ****
   
   

2. Type "SET PROCEDURE TO Test" (without quotes) in the Command window.

3. Type "? Bin_fld("memo1")" (without quotes) in the Command window.

The AFIELDS() function creates an array with specific information on each field in a chosen table. For example, the sixth element of the array created by the AFIELDS() function shows whether code page translation is allowed. This field contain a true (.T.) or false (.F.) value. If this element contains a true value in a Character or Memo field type, the field is binary. The TYPE() command handles any other field types. Entry of a nonexistent field name produces a "U," indicating undefined.

STATUS

This behavior is by design.

MORE INFORMATION

Character(Binary) or Memo (Binary) are not separate data types, as are Date, Currency, or Numeric types. The Binary versions of these fields prevent the field from conversion into another code page.

The NOCPTRANS clause on the CREATE TABLE or ALTER TABLE commands creates a binary Character or Memo field. This clause prevents a Character or Memo field from being translated into another code page. Since the NOCPTRANS clause works only on character or memo fields, these are the only field types in Visual FoxPro that can be either binary or non-binary. Some fields, however, are binary by design, such as Integer and General types. Therefore, the TYPE() function provides adequate information.

Steps to Reproduce Behavior

1. In the Command window, type the following command as one line:

         CREATE TABLE Test (char1 C(10), char2 C(10) NOCPTRANS, memo1 M(4),
         memo2 M(4) NOCPTRANS)
   

2. Type the following four lines in the Command window:

         ? TYPE("char1")
         ? TYPE("char2")
         ? TYPE("memo1")
         ? TYPE("memo2")