The system dictionary has 3 tables that are used exclusively to keep track of the JAR files and Java external procedure that are defined on your system. Those tables, and their respective purposes, are summarized in the following table.
| Table Name | Purpose |
|---|---|
| DBC.Jar_Jar_Usage | Contains 1 row for each JAR included in the SQL-Java path of another JAR. This is analogous to a #include directive in C and C++, where 1 JAR needs to include code from a different JAR. Therefore, if JAR A includes Jar B and Jar C, 1 row is inserted into DBC.Jar_Jar_Usage for the dependency of Jar A on Jar B, and 1 row is inserted for the dependency of Jar A on Jar C. You can only alter the SQL-Java path for a JAR by calling the external procedure SQLJ.Alter_Java_Path(), which means that a call to SQLJ.Alter_Java_Path() is the only action that can add rows to this table. For more information, see Teradata Vantage™ - SQL External Routine Programming, B035-1147. |
| DBC.Jars | Contains 1 row for each installed JAR. JARs can only be installed by means of a call to the SQLJ.Install_Jar() external procedure. Similarly, they can only be replaced by means of a call to the SQLJ.Replace_Jar() external procedure. For more information, see Teradata Vantage™ - SQL External Routine Programming, B035-1147. |
| DBC.Routine_Jar_Usage | Contains 1 row for each Java external procedure that names a JAR in its external Java reference string. The table indicates the dependency of a Java external procedure on a given JAR. For more information, see Teradata Vantage™ - SQL External Routine Programming, B035-1147. |
Columns for handling Jars also exist in the DBC.DBase, DBC.Dependency, and DBC.TVM tables. See Teradata Vantage™ - Data Dictionary, B035-1092 and Teradata Vantage™ - SQL External Routine Programming, B035-1147 for the structure of these tables and more information about their usage.