#

| Chapter 5 PL/Vision Package Specifications |

## 5.12 PLVfk: Foreign Key Interface

The PLVfk (PL/Vision Foreign Key) package is a high-level, easy-to-use interface to look up foreign key information in your tables. See Chapter 19 for details.

### 5.12.1 Package Constants

`c_prefix CONSTANT VARCHAR2(1) := 'P';`

  Specifies that the column abbreviation is to be used as a prefix.

`c_suffix CONSTANT VARCHAR2(1) := 'S';`

  Specifies that the column abbreviation is to be used as a suffix.

`c_no_change CONSTANT VARCHAR2(10) := 'NO CHANGE';`

  Used to indicate that no change is to be made to the string value.

`c_int_no_change CONSTANT INTEGER := 0;`

  Used to indicate that no change is to be made to the INTEGER value.

### 5.12.2 Setting the PLVfk configuration

`PROCEDURE set_vclen (length_in IN INTEGER);`

  Sets the default VARCHAR2 length for the foreign key named retrieved by the `PLVfk.name` function.

`PROCEDURE set_id_default`
`(string_in IN VARCHAR2 := c_no_change,`
`type_in IN VARCHAR2 := c_no_change);`

  Sets the default value to be used as the suffix or prefix of the name for the ID column.

`PROCEDURE set_nm_default`
`(string_in IN VARCHAR2 := c_no_change,`
`type_in IN VARCHAR2 := c_no_change);`

  Sets the default value to be used as the suffix or prefix of the name for the name column.

### 5.12.3 Looking up the name

>     FUNCTION name
>        (fk_id_in IN INTEGER,
>         fk_table_in IN VARCHAR2,
>         fk_id_col_in IN VARCHAR2 := c_no_change,
>         fk_nm_col_in IN VARCHAR2 := c_no_change,
>         max_length_in IN INTEGER := c_int_no_change,
>         where_clause_in IN VARCHAR2 := NULL)
>     RETURN VARCHAR2;

Retrieves the name for the specified table and ID.

### 5.12.4 Looking up the ID

>     FUNCTION id
>        (fk_nm_in IN VARCHAR2,
>         fk_table_in IN VARCHAR2,
>         fk_id_col_in IN VARCHAR2 := c_no_change,
>         fk_nm_col_in IN VARCHAR2 := c_no_change,
>         max_length_in IN INTEGER := c_int_no_change,
>         where_clause_in IN VARCHAR2 := NULL)
>     RETURN INTEGER;

Retrieves the ID (primary key) for the specified table and name or descriptor.

5.11 PLVfile: Operating System I/O Manager |  | 5.13 PLVgen: PL/SQL Code Generator

Copyright (c) 2000 O'Reilly & Associates. All rights reserved.