本章将教您如何在Derby中创建和删除过程.
您可以使用CREATE PROCEDURE创建过程声明.
以下是CREATE PROCEDURE语句的语法.
CREATE PROCEDURE procedure_name (parameter_type parameter_name1, parameter_type parameter_name2 . . . .) parameter_style;
假设我们在Derby中创建了一个表,如下所示.
CREATE TABLE Emp ( Id INT NOT NULL GENERATED ALWAYS AS IDENTITY, Name VARCHAR(255), Salary INT NOT NULL, Location VARCHAR(255), Phone_Number BIGINT );
并在其中插入值如下 :
INSERT INTO Employees(Name, Salary, Location) VALUES ('Amit', 30000, 'Hyderabad'), ('Kalyan', 40000, 'Vishakhapatnam'), ('Renuka', 50000, 'Delhi'), ('Archana', 15000, 'Mumbai'), ('Trupthi', 45000, 'Kochin')";
以下示例创建一个名为Update_Procedure的过程,该过程接受JAVA参数.
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
其中ProcedureExample类看起来像 :
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(); } }
您可以使用 SHOW PROCEDURES 查询验证程序列表.
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& . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
在这里你可以观察新创建的程序.
您可以使用DROP PROCEDURE语句删除过程.
以下是DROP PROCEDURE语句的语法.
DROP PROCEDURE procedure_name;
以下示例删除上面创建的名为Update_Procedure的过程.
ij> DROP PROCEDURE Update_Procedure; > 0 rows inserted/updated/deleted