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| Chapter 8 |

# 8. PLVtab: Easy Access to PL/SQL Tables

Contents:
Using PLVtab-Based PL/SQL Table Types
Displaying PLVtab Tables
Showing Header Toggle
Showing Row Number Toggle
Setting the Display Prefix
Emptying Tables with PLVtab
Implementing PLVtab.display

The PLVtab (PL/Vision TABle) package offers predefined PL/SQL table types and programs to make it easier to declare, use, and display the contents of PL/SQL tables. PL/SQL tables are the closest things to arrays in PL/SQL, but there are a number of complications. First, to use a PL/SQL table, you first have to declare a table type. Then you can declare and use the PL/SQL table itself. Beyond the definition of the PL/SQL table, the fact that it is a sparse, unbounded, homogeneous data structure can lead to complications, particularly when it comes to scanning and displaying those structures (see Chapter 10 of Oracle PL/SQL Programming).

By using PLVtab, you can avoid (in most cases) having to define your own PL/SQL table types. You can also take advantage of flexible, powerful display procedures to view table contents.

When you display the contents of PL/SQL tables, PLVtab allows you to:

- Show or suppress a header for the table

- Show or suppress the row numbers for the table values

- Display a prefix before each row of the table

This chapter shows how to use the different aspects of PLVtab.

## 8.1 Using PLVtab-Based PL/SQL Table Types

When you use PL/SQL tables, you normally perform a number of common actions, including defining the table type, declaring the table, filling up the rows, referencing the rows, and emptying the table when done. When using a PLVtab-based table, you do not have to declare the table type. Instead you simply reference the package-based type in your declaration. PLVtab predefines the following PL/SQL table TYPEs, shown in Table 8.1:

Table 8.1: Table Types Predefined in PLVtab
Type | Description
--- | ---
>     boolean_table
| PL/SQL table of Booleans
>     date_table
| PL/SQL table of dates
>     integer_table
| PL/SQL table of integers
>     number_table
| PL/SQL table of numbers
>     vc30_table
| PL/SQL table of VARCHAR2(30) strings
>     vc60_table
| PL/SQL table of VARCHAR2(60) strings
>     vc80_table
| PL/SQL table of VARCHAR2(80) strings
>     vc2000_table
| PL/SQL table of VARCHAR2(2000) strings
>     ident_table
| PL/SQL table of VARCHAR2(100) strings; matches `PLV.plsql_identifier` declaration.
>     vcmax_table
| PL/SQL table of VARCHAR2(32767) strings

Let's compare the "native" and PL/Vision approaches to defining PL/SQL tables. In the following anonymous block, I define a PL/SQL table of Booleans without the assistance of `PLVtab`.

>     DECLARE
>        TYPE bool_tabtype IS TABLE OF BOOLEAN
>           INDEX BY BINARY_INTEGER;
>        yesno_tab bool_tabtype;
>     BEGIN

With the `PLVtab` package in place, all I have to is the following:

>     DECLARE
>        yesno_tab PLVtab.boolean_table;
>     BEGIN

Once you have declared a table using PLVtab, you manipulate that table as you would a table based on your own table TYPE statement.

7.4 Controlling Output from p |  | 8.2 Displaying PLVtab Tables

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