The RAISE_ERROR function can be used to signal application program and data problems.
One situation where RAISE_ERROR may prove useful is in a CASE statement.
CASE WHEN SEX = ‘M’ THEN ‘MALE ‘
WHEN SEX = ‘F’ THEN ‘FEMALE’
ELSE RAISE_ERROR(’70SX1′, ‘INVALID DATA, SEX IS NEITHER F NOR M.’)
In Raise Error function, the first function is SQLSTATE. Second function is error decision.
Rules for SQLSTATE:
The value must be a character string of exactly five characters in length
Only the characters '0' through '9' and upper case 'A' through 'Z' may be used.
The first two characters cannot be '00', '01', or '02'.
If the first character is '0' through '6' or 'A' through 'H', the last three characters must start with a letter from 'I' through 'Z'.
If the first character is '7', '8', '9', or 'I' though 'Z', the last three characters can be any valid character.