CATALOG_METADATA_VIEWS¶

Description

The stored procedure CATALOG_METADATA_VIEWS returns information of the fields of the views. This information includes the type of the field, precision in case of numbers, etc.

You can filter by view and/or database.

Syntax

CATALOG_METADATA_VIEWS (
      input_database_name : text
    , input_view_name : text
)

• input_database_name: name of the database.

• input_view_name: name of the view you want to obtain its fields.

The procedure returns a row for each field of each view.

If input_database_name and input_view_name are NULL, the procedure returns the fields of all the views of all the databases.

If input_view_name is NULL, the procedure returns the fields of all the views of the input_database_name.

The output schema has the following fields:

• database_name: name of the database that the view of the field belongs to.

• view_name: name of the view’s field.

• view_type: type of the view:

  • 0: base view.

  • 1: derived view.

• column_name: name of the field.

• column_type_name: name of the type of the field in the “source type properties” of the field. E.g. VARCHAR, NCHAR, INTEGER, BIGINT, etc.

  These are the names of the constants defined in the class java.sql.Types of the JDBC API.

• column_type: number that represents the type of the field.

  The values of this field are defined in the class java.sql.Types of the JDBC API. E.g. INT = 4, VARCHAR = 12, etc.

• column_type_precision: its meaning depends on the type of the field:

  • For fields of type text, it indicates the maximum length of the field.

  • For numeric types, it indicates the precision. Therefore, for int and long fields, this number is 0.

• column_type_length: maximum length in bytes of the values of this field.

• column_type_scale: number of fractional digits that a value of this field could store.

Privileges Required

This procedure only returns information about the views on which the user has Read privileges. The implications of this are the following:

• If the user is an administrator, the procedure will return information about all the views of all the databases.

• The procedure will return information about the views of the databases on which the user is a local administrator.

• The procedure will return information about the views of the databases on which the user has Connect and Read privileges.

Note that this procedure does not return a “privileges error”. For example, let us say that:

• A user executes CALL CATALOG_METADATA_VIEWS (null, null) (i.e. obtain information about all the fields of all the views of all databases)

• This user only has Connect and Read privileges on the database testing.

In this scenario, the procedure only returns information about the views of the testing database and not about the views of the other databases.

Example

SELECT view_name, column_name, column_type_name, column_type_length
FROM CATALOG_METADATA_VIEWS()
WHERE input_database_name='chinook' and input_view_name = 'invoice';

The result is:

The query above is equivalent to the one below; the only difference is the syntax. The syntax above is more readable because you see what each parameter mean by its name.

CALL CATALOG_METADATA_VIEWS('chinook', 'invoice');