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Extending HCL OneDB™Beyond standard relational database objects, HCL OneDB™ can be extended to handle specialized data types, access methods, routines, and other objects. HCL OneDB™ includes many built-in extensions that are fully integrated in the database server. HCL OneDB™ also provides DataBlade® modules, which are packages of extended database objects for a particular purpose and that are installed separately from the database server. Alternatively, you can create your own user-defined objects for HCL OneDB™.
Creating extensionsYou can create user-defined data types, routines, access methods, and other database objects to suit your needs. You can use application programming interfaces to write user-defined routines and applications that access data in HCL OneDB™ databases.
J/Foundation Developer's GuideThe HCL® J/Foundation Developer's Guide describes how to write user-defined routines (UDRs) in the Java™ programming language for HCL OneDB™.
Create Java™ user-defined routinesA user-defined routine (UDR) is a routine that an SQL statement or another UDR can invoke. UDRs written in Java™ code use the server-side implementation of the HCL OneDB™ JDBC Driver to communicate with the database server.
Registering Java™ user-defined routinesFor a UDR to be invoked in an SQL statement, it must be registered in the current database. Use the CREATE FUNCTION and CREATE PROCEDURE statements to register UDRs.
Specify the external name

Specify the external name

The following diagram details the external-name portion of the CREATE ROUTINE (or FUNCTION or PROCEDURE) statement for a UDR written in Java™ code.

Java external name


Element	Purpose	Restrictions
class_name	Class to which the UDR belongs	Must be an existing class.
database	Database where the jar exists If omitted, defaults to the current database.	Must be an existing database.
jar_name	JAR identifier as specified in the install_jar() statement	Must be an existing JAR name.
java_datatype	Name of a Java data type The second column of the following table shows data types and class names that you can use for this variable.	Must be a Java data type.
method	Name of the static method of the UDR	Must be an existing method.
owner	Owner of the jar. If omitted, default is the current user.	Must be an existing user name.
package_name	Name of a package	Required if the UDR classes are in a package.

When used within a deployment descriptor, the THISJAR keyword automatically expands to the SQLJ-defined three-part JAR path.

The following table shows mapping between SQL data values and Java types. Use the values in the second column for the java_datatype variable.

Table 1. Mapping between SQL data values and Java types
SQL data type	Java type
CHAR(1)	char
CHAR(1)	java.lang.Character
CHAR()	Java.lang.String
CHARACTER()	java.lang.String
CHARACTER VARYING()	java.lang.String
VARCHAR	java.lang.String
LVARCHAR	java.lang.String
SMALLINT	short
SMALLINT	java.lang.Short
INTEGER	int
INTEGER	java.lang.Integer
INT8	long
INT8	java.lang.Long
SMALLFLOAT	float
SMALLFLOAT	java.lang.Float
REAL	float
REAL	java.lang.Float
FLOAT	double
FLOAT	java.lang.Double
DOUBLE PRECISION	double
DOUBLE PRECISION	java.lang.Double
DECIMAL	java.math.BigDecimal
MONEY	java.math.BigDecimal
NUMERIC	java.math.BigDecimal
BOOLEAN	boolean
BOOLEAN	java.lang.Boolean
DATE	java.sql.Date
DATETIME HOUR TO SECOND	java.sql.Time
DATETIME YEAR TO FRACTION	java.sql.Timestamp
INTERVAL	java.lang.String
BLOB	java.sql.Blob
CLOB	java.sql.Clob