MAP OBJECT Statement - PL/HQL Reference

MAP OBJECT statement allows you to map an object (table or view) to a connection profile. You can also use this statement to map an object name used in a PL/HQL script to the actual object name in the database.

Depending on the connection profile linked to the object, PL/HQL can work with multiple databases to access different objects in a single PL/HQL script.

For example, you can send queries to Hive and use a RDBMS or NoSQL database for logging.

Syntax:

MAP OBJECT source_name [TO target_name] [AT connection_profile];

Notes:

• source_name - the object name used in PL/HQL scripts
• target_name - the object name that actually used when accessing the database
• connection_profile - the connection profile used to access this object. If the profile is not specified the default profile is used.
• At least target_name or connection_profile must be specified
• source_name, target_name and connection_profile are expressions, so you can define them dynamically.

Example:

Query Hive and write log messages to a MySQL database:

MAP OBJECT log TO log.log_data AT mysqlconn;
 
DECLARE cnt INT;
SELECT count(*) INTO cnt FROM sales.users WHERE local_dt = CURRENT_DATE;
 
INSERT INTO log (message) VALUES ('Number of users: ' || cnt);  

Compatibility: PL/HQL extension

Version: PL/HQL 0.3.1