Oracle PL/SQL for DBAs

Literals

A literal is a value that is not represented by an identifier; it is simply a value.

String literals

A string literal is text surrounded by single quote characters, such as:

    'What a great language!'

Unlike identifiers, string literals in PL/SQL are case-sensitive. As you should expect, the following two literals are different.

    'Steven'
    'steven'

So the following condition evaluates to FALSE:

    IF 'Steven' = 'steven'

Numeric literals

Numeric literals can be integers or real numbers (a number that contains a fractional component). Note that PL/SQL considers the number 154.00 to be a real number of type NUMBER, even though the fractional component is zero and the number is actually an integer. Internally, integers and reals have a different representation, and there is some small overhead involved in converting between the two.

You can also use scientific notation to specify a numeric literal. Use the letter “E” (upper- or lowercase) to multiply a number by 10 to the nth power—for example, 3.05E19, 12e-5.

Beginning in Oracle Database 10g Release 1, a real can be either an Oracle NUMBER type or an IEEE 754 standard floating-point type . Floating-point literals are either binary (32-bit) (designated with a trailing F) or binary double (64-bit) (designated with a trailing D).

In certain expressions, you may use the named constants summarized in Table 1-3 as prescribed by the Institute of Electrical and Electronics Engineers (IEEE) standard.

Table 1-3. Named constants for BINARY_FLOAT and ...