JDBC Type 2 Driver Programmer's Reference for SQL/MX Release 3.2.1 (H06.26+, J06.15+)

-out - Write the SQL statements to <filename>.

-bigblock - Generates SQL statement to create LOB column size of 24K bytes and attribute block size of 32K.

<clobTableName> | <blobTableName> is:

<table_name> is:

[<catalogName>.][<schemaName>.]<baseTableName>

<baseTableName> is the table that contains LOB column(s).

<lobTableName> is the table that contains the LOB data.

Using SQL/MX Triggers to Delete LOB Data

Use the JDBC/MX Lob Admin Utility to generate triggers to delete LOB data from the LOB table

when the base row is deleted. These triggers ensure that orphan LOB data does not occur in the

LOB table. To manage the triggers, use these JDBC/MX Lob Admin Utility options:

-trigger

Generates SQL statements to create triggers.

-drop

Generates SQL statements to drop triggers.

For example, the following command (typed on one line) generates the SQL statements to create

the triggers for the base table sales.paris.pictures, which contains a BLOB column, and

executes those statements.

java -Djdbcmx.blobTableName=sales.paris.lobTable4pictures JdbcMxLobAdmin -trigger

-exec sales.paris.pictures

Limitations of the CLOB and BLOB Data Types

Limitations of the CLOB and BLOB data types, collectively referred to as LOB data, are:

• LOB columns can only be in the target column list of these SQL statements:

INSERT statement◦

◦ Select list of a SELECT statement

◦ Column name in the SET clause of an UPDATE statement

• LOB columns cannot be referenced in the SQL/MX functions and expressions.

• LOB data is not deleted from the LOB table when the base row is deleted unless a trigger is

established. For information about triggers, see “Using SQL/MX Triggers to Delete LOB Data”

(page 57).

• LOB data is not accessible if the base table name is changed.

• LOB columns cannot be copied to another table by using the SQL/MX utility commands.

• The name of a base table that has CLOB or BLOB columns must be unique across all catalogs

and schemas when more than one of these base tables share a single LOB table.

Using SQL/MX Triggers to Delete LOB Data 57