Oracle9i + pl_ SQL Study Notes

Index Table
Index-by tables is a bit similar to a database table, which consists of two columns (key and value ). Its key value type is binary_integer, and value type is the type specified in the definition. Unlike a database table, it is a table stored in memory.
Define index table:
Type type_name is table of element_type [not null]
Index by binary_integer;
Type_name: name of the defined type, which declares the index table variable.
Element_type: Declares the Data Type of the value in the index table.
Not null is optional. If not null is specified, a null value cannot be inserted.
Index by binary_integer is used to mark the index table. If not, it is a nested table by default.
Type my_table is table of varchar2 (30) index by binary_integer;
V_mt my_table;
The value of the index table can be a scalar type or a record type.
Type mytable is table of Treader. % rowtype index of binary_integer;
Insert data to the index table
After defining the types and variables, you can use mytable [Key] to reference a single element in the index table. Mytable [Key]: = value.
Nested table
The nested table is similar to the index table. The difference is that the nested table can be saved to the database, but the index table cannot.
Declaration: Type type_name is table of element_type [not null]
Nested assignment:
Declare
Type test is table of varchar2 (10 );
Mt test: = test ('fan ', 'hao ');
Begin
Dbms_output.put_line (MT (1) | ''| MT (2 ));
End;
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