CHECK (Check) keyword for physical and logical files

You can use this field-level keyword to specify validity checking in display files.

The format of the keyword is:

CHECK(edit-check-code [. . .])

The CHECK keyword does not affect the physical or logical file that is defined. When you define an input-capable field in a display file, refer to the field you are defining by specifying R in position 29 and using the REF or REFFLD keyword. At display file creation, the operating system copies the CHECK keyword and other field attributes from the field in the physical or logical file into the field in the display file. You can override the CHECK keyword (as well as all other validity checking keywords and the CHKMSGID keyword) by specifying any validity checking keyword for the field in the display file.

The rules for specifying this keyword in a physical or logical file are similar to those for a display file. However, only the following codes are allowed in physical or logical files:

Code: Meaning
AB: Allow blank
ME: Mandatory enter
MF: Mandatory fill
M10: IBM® Modulus 10 self-check algorithm
M10F: IBM Modulus 10 self-check algorithm
M11: IBM Modulus 11 self-check algorithm
M11F: IBM Modulus 11 self-check algorithm
VN: Validate name
VNE: Validate name extended

You cannot specify the CHECK(AB), CHECK(VN), CHECK(VNE), CHECK(M10), CHECK(M11), CHECK(M10F), or CHECK(M11F) keywords on a floating-point field (F in position 35). You cannot specify the CHECK keyword on a hexadecimal field (H in position 35). Do not specify the CHECK keyword on a date, time, or timestamp field (L, T, or Z in position 35).