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A cursor variable declared in a PL/SQL hosting environment and passed to PL/SQL as a binding variable. The data type of the host cursor variable is compatible with the return type of any PL/SQL cursor variable. Host variables must be preceded by a colon. Initially, A and B are initialized with 3 and 5, respectively, while C is not initialized. The first assignment statement sets the value from A to C, giving A=3, B=5, and C=3. The value of a variable can be changed. If x e.B. is set to 5, the mapping statement is an attribute of an object type. The name must be unique in the object type (but can be reused in other object types). You cannot initialize an attribute in its declaration by using the mapping operator or the DEFAULT clause. Additionally, you cannot impose the NOT NULL constraint on an attribute. A combination of variables, constants, literals, operators, and function calls.

The simplest expression consists of a single variable. For more information about expression syntax, see Expressions. When the assignment statement is executed, the expression is evaluated and the resulting value is stored in the mapping target. The value and destination must have compatible data types. An instance of an object type previously declared in the current range. The formal out or IN OUT parameter of the subroutine in which the assignment statement occurs. An assignment statement assigns a value to a variable. For example, a mapping statement defines the current value of a variable, field, parameter, or element. The statement consists of a mapping target followed by the mapping 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 Assigning Values to Variables. The previously declared pl/sql cursor variable in the current range. Only the value of another cursor variable can be assigned to a cursor variable. The second assignment statement calculates the sum of the current value of Counter and 3 and stores the result in Counter. Therefore, the new value of Counter is 1 + 3 = 4. An indicator variable declared in a PL/SQL hosting environment and passed to PL/SQL. The variables in the indicator must be preceded by a colon. An indicator variable “specifies” the value or condition of the associated host variable. For example, in the Oracle Precompiler environment, you can use flag variables to detect null values or truncated values in the output host variables.

You can assign values to all fields in a record at the same time. PL/SQL allows aggregated mapping between entire records when their declarations point to the same cursor or table. The following example copies the values of all fields from one record to another: the second assignment statements set the value from B to A. This destroys the original value of A3. After that, A = 5, B = 5 and C = 3. The meaning of the first assignment is to calculate the sum of the value in the counters and 1 and store them in the meters. Since the current value of Counter is zero, Counter + 1 is 1 + 0 = 1 and therefore 1 is stored in Counter. Therefore, the new value changes from counter to 1 and its original value 0 disappears. The third assignment statement sets the value from C to B. This results in A = 5, B = 3 and C = 3. Therefore, the values of A and B are exchanged.

A “statement” association is not really a statement (although it is usually used this way), but an expression. The value of the expression is the value assigned to the variable. For example, the expression You can map the result of a comparison or other test to a Boolean variable. . Only true, false, and null can be assigned to a Boolean variable. By default, unless a variable is initialized in its declaration, it is initialized to NULL each time a block or subroutine is entered. Always set a value to a variable before using that variable in an expression. Constants and variables, expressions, SELECT INTO Statement A numeric expression that must return a value of type BINARY_INTEGER or a value that can be implicitly converted to that type of data. You can assign the value of an expression to a specific field in a record. .

You cannot assign zeros to a variable that is defined as NOT NULL. When you try, PL/SQL resolves the predefined exception VALUE_ERROR. . .