PL/SQL data type

1. Variables and Constants
Variable syntax: variable_name data_type [[Not NULL] [: =value]
Description: NOT NULL defines a non-null constraint on a variable, a variable must be assigned a non-null initial value, and its value is not allowed to be modified to null at any time.

--Examples of variables:

Sql>serverout onsql>declare v_num Number (4);  BEGIN v_num:=20; Dbms_output. The value of put_line (' variable name v_num is: ' | | V_num); END; /

Constant syntax: Constant_name constant Data_type [: =value]

--Examples of constants:

DECLARE c_num CONSTANT Number (4): = 100; BEGIN Dbms_output. The value of Put_Line (' Constant name c_num: ' | | C_num); END;

2. Composite data type

2.1%type Type

The type of a column that references a variable or database is used as the data type of a variable.

SET serverout ondeclare v_ename scott.emp.ename%type;    V_sal1 number (11); V_sal2 V_sal1%type;    BEGIN SELECT ename,sal to V_ename,v_sal1 from Scott.emp WHERE empno=7369;    V_sal2:=v_sal1; Dbms_output. Put_Line (v_ename| | ' The wages are ' | | V_SAL2); END

2.2%rowtype

Refers to a row in a database table as the data type, that is, the record type, which is the additional type of PL/SQL. Represents a record, equivalent to an object in Java. You can use the "." To access the properties in the record.

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PL/SQL data type