[bbk5153]第15集 - Chapter 06- Working with Composite Data Types(Collection)

Nested Tables

[表中有表]

关联数组，是用在PL/SQL中的一种普通数据类型，无法存储在数据库中；嵌套表既可以在PL/SQL中使用，也可以存储在数据库中.

VARRAY

可变数组，既可以在PL/SQL中使用，也可以存储在数据库中.

Summary of Collection Types

Quiz

Identify situations in which you can use the %ROWTYPE attribute.

When you are not sure about the structure of the underlying database table.

When you want to retrieve an entire row from a table.

When you want to declare a variable according to another previously declared bariable or database column.

锚锁定技术有两类，一类是Scalar变量的锁定，一类是Record的锁定；Scalar的锁定使用%TYPE,Record的锁定使用%ROWTYPE;

Summary

In this lesson,you should have learned to:

Define and reference PL/SQL variables of composite data types

-PL/SQL record

-Associative array

-INDEX BY table

-INDEX BY table of records

Define a PL/SQL record by using the %ROWTYPE attribute

Compare and contrast the three PL/SQL collection types:

-Associative array

-Nested table

-VARRAY