Causes DEC DATATRIEVE to repeat a statement as long as the condition specified in the Boolean expression is true. Format WHILE boolean-expression statement
1 – Arguments
boolean-expression Is a Boolean expression. In the WHILE statement, Boolean expressions are limited to the following format: { variable-name } { *.prompt } boolean-operator value-expression { } statement Is a simple or compound statement you want DEC DATATRIEVE to execute if the Boolean expression evaluates to true.
2 – Example
The following example groups the boats with LOA less than 35 according to the value of BEAM and displays the TYPE, LOA, and BEAM of the shortest boat from each group of boats with the same value for BEAM: DTR> SHOW WHILE_EX PROCEDURE WHILE_EX BEGIN DECLARE X PIC 99. X = 0 FOR YACHTS WITH LOA < 35 AND BEAM NE 0 SORTED BY BEAM, LOA WHILE X < BEAM BEGIN PRINT TYPE, LOA, BEAM, X X = BEAM END END END_PROCEDURE DTR> :WHILE_EX LENGTH OVER MANUFACTURER MODEL ALL BEAM X CAPE DORY TYPHOON 19 06 00 WINDPOWER IMPULSE 16 07 06 ERICSON 23/ SPECIA 23 08 07 EASTWARD HO 24 09 08 ALBIN 79 26 10 09 BOMBAY CLIPPER 31 11 10 IRWIN 25 25 12 11 DTR>