|PL/SQL User's Guide and Reference
Release 2 (9.2)
Part Number A96624-01
PL/SQL Language Elements, 2 of 52
An assignment statement sets the current value of a variable, field, parameter, or element. The statement consists of an assignment target followed by the assignment operator and an expression. When the statement is executed, the expression is evaluated and the resulting value is stored in the target. For more information, see "Variable Assignment".
This identifies an attribute of an object type. The name must be unique within the object type (but can be reused in other object types). You cannot initialize an attribute in its declaration using the assignment operator or
DEFAULT clause. Also, you cannot impose the
NULL constraint on an attribute.
This identifies a nested table, index-by table, or varray previously declared within the current scope.
This identifies a PL/SQL cursor variable previously declared within the current scope. Only the value of another cursor variable can be assigned to a cursor variable.
This is an arbitrarily complex combination of variables, constants, literals, operators, and function calls. The simplest expression consists of a single variable. For the syntax of
expression, see "Expressions". When the assignment statement is executed, the expression is evaluated and the resulting value is stored in the assignment target. The value and target must have compatible datatypes.
This identifies a field in a user-defined or
This identifies a cursor variable declared in a PL/SQL host environment and passed to PL/SQL as a bind variable. The datatype of the host cursor variable is compatible with the return type of any PL/SQL cursor variable. Host variables must be prefixed with a colon.
This identifies a variable declared in a PL/SQL host environment and passed to PL/SQL as a bind variable. Host variables must be prefixed with a colon.
This is a numeric expression that must yield a value of type
BINARY_INTEGER or a value implicitly convertible to that datatype.
This identifies an indicator variable declared in a PL/SQL host environment and passed to PL/SQL. Indicator variables must be prefixed with a colon. An indicator variable "indicates" the value or condition of its associated host variable. For example, in the Oracle Precompiler environment, indicator variables let you detect nulls or truncated values in output host variables.
This identifies an object (instance of an object type) previously declared within the current scope.
This identifies a formal
OUT parameter of the subprogram in which the assignment statement appears.
This identifies a user-defined or
%ROWTYPE record previously declared within the current scope.
This identifies a PL/SQL variable previously declared within the current scope.
By default, unless a variable is initialized in its declaration, it is initialized to
NULL every time a block or subprogram is entered. So, never reference a variable before you assign it a value.
You cannot assign nulls to a variable defined as
NULL. If you try, PL/SQL raises the predefined exception
Only the values
NULL can be assigned to a Boolean variable. When applied to an expression, the relational operators return a Boolean value. So, the following assignment is legal:
DECLARE out_of_range BOOLEAN; ... BEGIN ... out_of_range := (salary < minimum) OR (salary > maximum);
As the next example shows, you can assign the value of an expression to a specific field in a record:
Moreover, you can assign values to all fields in a record at once. PL/SQL allows aggregate assignment between entire records if their declarations refer to the same cursor or table. For example, the following assignment is legal:
DECLARE emp_rec1 emp%ROWTYPE; emp_rec2 emp%ROWTYPE; dept_rec dept%ROWTYPE; BEGIN ... emp_rec1 := emp_rec2;
Using the following syntax, you can assign the value of an expression to a specific element in a collection:
In the following example, you assign the uppercase value of
last_name to the third row in nested table
Several examples of assignment statements follow:
wages := hours_worked * hourly_salary; country := 'France'; costs := labor + supplies; done := (count > 100); dept_rec.loc := 'BOSTON'; comm_tab(5) := sales * 0.15;