This chapter teaches you how to create and drop procedures in Derby.
Creating a procedure
You can create a procedure using the CREATE PROCEDURE statement.
Syntax
Following is the syntax of the CREATE PROCEDURE statement.
CREATE PROCEDURE procedure_name (parameter_type parameter_name1, parameter_type parameter_name2 . . . .) parameter_style;
Example
Suppose, we have created a table in Derby as shown below.
CREATE TABLE Emp ( Id INT NOT NULL GENERATED ALWAYS AS IDENTITY, Name VARCHAR(255), Salary INT NOT NULL, Location VARCHAR(255), Phone_Number BIGINT );
And inserted values in it as follows −
INSERT INTO Employees(Name, Salary, Location) VALUES
('Amit', 30000, 'Hyderabad'),
('Kalyan', 40000, 'Vishakhapatnam'),
('Renuka', 50000, 'Delhi'),
('Archana', 15000, 'Mumbai'),
('Trupthi', 45000, 'Kochin')";
Following example creates a procedure named Update_Procedure which accepts JAVA parameters.
ij> CREATE PROCEDURE Update_Procedure(IN id INTEGER, IN name VARCHAR(10)) PARAMETER STYLE JAVA READS SQL DATA LANGUAGE JAVA EXTERNAL NAME 'ProcedureExample.testProc'; > 0 rows inserted/updated/deleted
Where ProcedureExample class looks like −
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
public class ProcedureExample {
public static void testProc(int salary, String name) throws Exception {
String connectionURL = "jdbc:derby:MYDATABASE;create=true";
Connection conn = DriverManager.getConnection(connectionURL);
String query = "UPDATE Employees SET SALARY = ? WHERE NAME = ?";
PreparedStatement pstmt = conn.prepareStatement(query);
pstmt.setInt(1, salary);
pstmt.setString (2, name);
pstmt.executeUpdate();
}
}
You can verify the list of procedures using SHOW PROCEDURES query.
ij> SHOW PROCEDURES; PROCEDURE_SCHEM |PROCEDURE_NAME |REMARKS ------------------------------------------------------------------------ APP |UPDATE_PROCEDURE |ProcedureExample.te& SALES |EXAMPLE_ PROCEDURE |com.example.sales.c& SQLJ |INSTALL_JAR |org.apache.derby.ca& SQLJ |REMOVE_JAR |org.apache.derby.ca& SQLJ |REPLACE_JAR |org.apache.derby.ca& SYSCS_UTIL |SYSCS_BACKUP_DATABASE|org.apache.derby.ca& . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Here you can observe the newly created procedure.
Dropping a procedure
You can drop a procedure using the DROP PROCEDURE statement.
Syntax
Following is the syntax of the DROP PROCEDURE statement.
DROP PROCEDURE procedure_name;
Example
Following example drops a procedure named Update_Procedure created above.
ij> DROP PROCEDURE Update_Procedure; > 0 rows inserted/updated/deleted