Chapter 7. Nested Tables

Question 1

Q:

Answer

7-1.

The syntax for creating a nested table is similar to that for an index-by table:

TYPE type name IS TABLE OF element datatype [NOT NULL];

For example, here’s the command to create a nested table type called a_simple_udt_t; its elements consist of numeric data, each with no more than 10 digits:

CREATE TYPE a_simple_udt_t IS TABLE OF NUMBER(10);

Answer

7-2.

The statements are:

True. Nested table types can indeed be used as datatypes for Oracle tables as in this DDL:
```
SQL> CREATE TABLE a_table (
  2    col1 number,
  3    col2 a_simple_udt_t )
  4  NESTED TABLE col2 STORE AS a_table_col2;

Table created.
```
The NESTED TABLE clause specifies the name of the table used to store the data in the nested column.
True. Whether a nested table type is used as a column in a table or in PL/SQL itself, there is no limit to the number of rows it can store.
False. All rows in a nested table must contain the same type of data.
True. Nested table types are stored in the database. To view information about the nested table types in a database including their structure, use the data dictionary views ALL_TYPES and ALL_TYPE_ATTRS.
False. Nested table types can be based on user-defined data types as well as Oracle’s native data types. For example, you can create an object as:
```
SQL> CREATE TYPE an_object_t AS OBJECT (
  2     column_one VARCHAR2(30),
  3     column_two NUMBER(10,2) );

Type created.
```
And then create a nested table type based on the object as:
```
SQL> CREATE TYPE a_nested_table_t AS TABLE OF an_object_t; ...
```

Question 2

Q:

Oracle PL/SQL Programming: A Developer's Workbook by Steven Feuerstein, Andrew Odewahn

Chapter 7. Nested Tables

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Q:
7-1.	The syntax for creating a nested table is similar to that for an index-by table: TYPE `type` `name` IS TABLE OF `element datatype` [NOT NULL]; For example, here’s the command to create a nested table type called a_simple_udt_t; its elements consist of numeric data, each with no more than 10 digits: CREATE TYPE a_simple_udt_t IS TABLE OF NUMBER(10);
Q:
7-2.	The statements are: True. Nested table types can indeed be used as datatypes for Oracle tables as in this DDL: SQL> CREATE TABLE a_table ( 2 col1 number, 3 col2 a_simple_udt_t ) 4 NESTED TABLE col2 STORE AS a_table_col2; Table created. The NESTED TABLE clause specifies the name of the table used to store the data in the nested column. True. Whether a nested table type is used as a column in a table or in PL/SQL itself, there is no limit to the number of rows it can store. False. All rows in a nested table must contain the same type of data. True. Nested table types are stored in the database. To view information about the nested table types in a database including their structure, use the data dictionary views ALL_TYPES and ALL_TYPE_ATTRS. False. Nested table types can be based on user-defined data types as well as Oracle’s native data types. For example, you can create an object as: SQL> CREATE TYPE an_object_t AS OBJECT ( 2 column_one VARCHAR2(30), 3 column_two NUMBER(10,2) ); Type created. And then create a nested table type based on the object as: SQL> CREATE TYPE a_nested_table_t AS TABLE OF an_object_t; ...