A value expression is a symbol or string of symbols that you
use to calculate a value. When you use a value expression in
a statement, Oracle Rdb calculates the value associated with the
expression and uses it when executing the statement.
The RDML value expressions are:
o Arithmetic
o Database Field Value
o FIRST FROM
o Host Variable
o RDB$DB_KEY
o RDB$MISSING
For more information and the syntax diagrams see the HELP entries
for each of these expressions.
1 – Format
(B)0[mvalue-expr =
qqqwqqq> host-variable qqqqqqqqqqqqwqqq>
tqqq> db-field qqqqqqqqqqqqqqqqqu
tqqq> quoted-string qqqqqqqqqqqqu
tqqq> numeric-literal qqqqqqqqqqu
tqqq> statistical-expr qqqqqqqqqu
tqqq> arithmetic-expr qqqqqqqqqqu
tqqq> missing-value qqqqqqqqqqqqu
tqqq> first-expr qqqqqqqqqqqqqqu
tqqq> concat-expr qqqqqqqqqqqqqqu
tqqq> dbkey qqqqqqqqqqqqqqqqqqqu
tqqq> ( qq> value-expr qq> ) qqqu
tqqq> - qq> value-expr qqqqqqqqu
mqqq> + qq> value-expr qqqqqqqqj
The concat-expr consists of the concatenate operator ( | ) and
two value expressions. The concat-expr joins the second value
expression to the first value expression.