Chapter 7. Nested Tables

In addition to simply renaming PL/SQL tables to index-by tables in Oracle8, Oracle introduced two new collection datatypes: nested arrays and variable arrays. While conceptually similar to index-by tables, the two new collection types are usable in SQL statements (for example, you can insert multiple rows of a collection into a table via Oracle 8i Release 8.1’s bulk collection operators) and may be stored as columns in a database table. This chapter tests your understanding of nested tables, the first of the new collection types. Specifically, it examines your ability to create a nested table type, store the array in a “store table,” add and delete elements, and traverse each element.

Beginner

7-1.

What SQL syntax is introduced in Oracle8 to create nested table types?

7-2.

True or false?

  1. Nested table types can be used as datatypes for columns in Oracle tables.

  2. There is no limit to the number of rows that can be stored in a nested table type.

  3. Different rows in a nested table type can contain different types of information. Row 1, for example, might contain numeric data while Row 2 contains a string.

  4. Nested table types are stored in the database.

  5. Nested table types can be created based only on Oracle’s native datatypes such as VARCHAR2 and NUMBER.

7-3.

Fixit Later is the System Architect at Simplistic Procurement Systems, and he has executed the following DDL to create a new system:

SQL> CREATE TYPE detail_t AS OBJECT ( detail_no PLS_INTEGER, 2 detail_desc VARCHAR2(30), ...

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