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Table comment definition
A comment consisting of a character string can be specified for a table. A character string of up to 256 bytes can be
specified. If no comment is necessary, omit the specification. An example follows.
Example:
Specify a character string comment for the STOCK table.
2.6.4 Table definition for multimedia data storage
This section explains how to define a table that stores data types such as image and voice. This type of data is stored
in a BLOB-type column.
To define a BLOB-type column of 31 kilobytes or more, specify SEQUENTIAL or OBJECT as the table storage
structure.
If OBJECT is used as the data storage structure, the following conditions are added to the definition of a table for
storing numeric values and characters.
1. Only one BLOB-type column for data exceeding 31 kilobytes can be specified, and the column must be
specified as the last column in the table.
2. The NOT NULL constraint must be specified for the column described in item 1.
3. The data type for columns other than the column described in item 1. must be fixed length.
4. An ALTER TABLE statement for changing a table definition cannot be described in item 1.
For more information on storage structure, refer to "2.7 Definition of Storage Structure."
Example:
The following is an example in which the PRODPHOT table is defined in schema S1 when
SEQUENTIAL is used as the data storage structute. In this sample, ITMNO is defined as a column for
non-BLOB-type data. Next, PRODPHOTO is defined as a column for one-megabyte BLOB-type data.
2.6.5 View definition
Define a view using the CREATE VIEW statement. Views are used to simplify data manipulations by application
programs and to join multiple tables and process them as a single table. Views are also used to increase the
independence of application programs and data.
A view definition defines the following items:
· Table name (view name)
· View column list
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