Description

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 specify the partitioning in the PARTITION ON clause. 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 stream 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.

Example

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;