CREATE PROCEDURE FROM CLASS — Defines a stored procedure associated with a Java class.
[PARTITION ON TABLE table-name COLUMN column-name [PARAMETER position]]
[ALLOW role-name [,...]]
FROM CLASS class-name
You must declare stored procedures to make them accessible to client applications and the sqlcmd utility. CREATE PROCEDURE FROM CLASS lets you declare stored procedures that are written as Java classes.The class-name is the name of the Java class.
Before you declare the stored procedure, you must create, compile, and load the associated Java class. It is usually easiest to do this by compiling all of your Java stored procedures and packaging the resulting class files into a single JAR file that can be loaded once. For example:
$ javac -d ./obj src/procedures/*.java $ jar cvf myprocs.jar –C obj . $ sqlcmd 1> load classes myprocs.jar; 2> CREATE PROCEDURE FROM CLASS procedures.AddCustomer;
When creating single-partitioned procedures, you can either specify the partitioning in a separate PARTITION PROCEDURE statement or you can include the PARTITION ON clause in the CREATE PROCEDURE statement. Creating and partitioning stored procedures in a single statement is recommended because there are certain cases where procedures with complex queries must be partitioned and cannot be compiled without the partitioning information. For example, queries that join two partitioned tables must be run in a single-partitioned procedure and must join the tables on their partitioning columns.
Partitioning a stored procedure means that the procedure executes within a unique partition of the database. The partition in which the procedure executes is chosen at runtime based on the table and column specified by table-name and column-name. By default, VoltDB uses the first parameter to the stored procedure as the partitioning value. However, you can use the PARAMETER clause to specify a different parameter. The position value specifies the parameter position, counting from zero. (In other words, position 0 is the first parameter, position 1 is the second, and so on.)
The specified table must be a partitioned table and cannot be an export-only or replicated table.
If security is enabled at runtime, only those roles named in the ALLOW clause (or with the ALLPROC or ADMIN permissions) have permission to invoke the procedure. If security is not enabled at runtime, the ALLOW clause is ignored and all users have access to the stored procedure.
The following example declares a stored procedure matching the Java class MakeReservation. Note that the class name includes its location within the current class path (in this case, as a child of flight and procedures). However, the name itself, MakeReservation, must be unique within the schema because at runtime stored procedures are invoked by name only.
CREATE PROCEDURE FROM CLASS flight.procedures.MakeReservation;