COP4540 TUTORIAL PROFESSOR: DR SHU-CHING CHEN TA: H S IN-YU HA

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1 COP4540 TUTORIAL PROFESSOR: DR SHU-CHING CHEN TA: H S IN-YU HA

2 OUTLINE Postgresql installation Introduction of JDBC Stored Procedure

3 POSTGRES INSTALLATION (1) Extract the source file Start the configuration (about one minute) Set up the prefix as the folder with your own permission Default would be home directory.

4 POSTGRES INSTALLATION (2) Compile all of your source code If the code was built correctly the last line would be Ready to install (less than one minute) Successfully install

5 POSTGRES INSTALLATION (3) Initialize database cluster Start the postgres server

6 OUTLINE Postgresql installation Introduction of JDBC Stored Procedure

7 JDBC Write once, Match all DBMS!! The Java Database connectivity Making a connection to a database Creating SQL or MySQL statements Executing queries in the database Viewing or Modifying the result records Oracle JDBC Driver Oracle Database Application JDBC Driver Interface SQL JDBC Driver MySQL JDBC Driver PostgreSQL JDBC Driver SQL Database MySQL Database PostgreSQL Database

8 STEPS OF CONNECTING DATABASE 1) Get the specific type of JDBC driver 2) Initializing the Driver 3) Start the Connection 4) Initialize one Statement object 5) Send out the SQL execute*() 6) Get the Resultset object which is returned by DBMS 7) Close the connection close()

9 (1) GET JDBC DRIVER Download driver from any DBMS company website Format: <DBMS_Name-JDBC-Type_n.jar> For example: postgresql jdbc4.jar j Put it to any accessible library folder PostgreSQL JDBC Driver :

10 (2) INITIALIZING THE DRIVER Importing JDBC Import java.sql.* Loading the server Class.forName("org.postgresql.Driver"); try { Class.forName("org.postgresql.Driver"); t l D i ") }catch(classnotfoundexception e) { System.out.println( Can t find Driver class "); }

11 (3) START THE CONNECTION String DRIVER = "org.postgresql.driver Driver"; String URL ="jdbc:postgresql://[ip]:5432/[db_name]"; String USER = "whoami"; String PASSWORD = "123456"; Connection conn = DriverManager.getConnection( getconnection( URL, USER, PASSWORD ); // DriverManager.getConnection( url ); System.out.println(conn.isReadOnly( ));... if ( conn!= null &&!conn.isclosed( ) ) { System.out.println( Successfully connect to database!"); } conn.close( );

12 (4) INITIALIZE ONE STATEMENT OBJECT AND (5)EXECUTE Statements stmt = conn.createstatement( ); ResultSet result = stmt.executequery( SELECT * FROM mytable ); Execute executequery() -> SQL for Searching and viewing executeupdate() -> SQL for Changing database s contents ExecuteQuery() Return results as row(s) () Use next() to move to next record, return a boolean value to indicate whether we have next record Use get<type>() to retrieve the data by attribute name or order

13 EXECUTE EXAMPLE Create / Update table Statements stmt = conn.createstatement( ); stmt.executeupdate( "CREATE TABLE jdemo ( title character varying(50),body text, id serial)"); stmt.executeupdate( ALTER TABLE jdemo ADD PRIMARY KEY (id) ); View data ResultSet result = stmt.executequery( executequery( SELECT * FROM jdemo ); while (result.next( )) { System.out.print(result.getInt( id ) + \t ); System.out.print(result.getString("title") + "\t"); System.out.println(result.getString("body")); i ( }

14 JDBC EXAMPLE 1. Import java.sql.*; 2. public class BasicResultSetExample { 2. public class BasicResultSetExample { 3. public static void main(string[] args) { 4. try{ 5. /** Loading the driver*/ 6. Class.forName(org.postgresql.Driver); 7. /** Getting Connection*/ 8. Connectioncon = DriverManager.getConnection(jdbc:postgresql://localhost:5432/test,root,root); 9. /** Creating Statement*/ 10. Statementstmt =con.createstatement(); 11 ResultSetrs=stmt executequery(select * from mytable); 11. ResultSetrs=stmt.executeQuery(select from mytable); 12. while(rs.next()) 13. { 14. System.out.print(Id is +rs.getint(id)); 15. System.out.println( Name is +rs.getstring(name)); 16 } 16. } 17. /** Closing the Connection*/ 18. stmt.close(); 19. con.close(); 20. }catch (Exceptione) { } ( p ){ 21. e.printstacktrace();} 22. } 23. }

15 OUTLINE Postgresql installation Introduction of JDBC Stored Procedure

16 WHAT ARE STORED PROCEDURES A stored procedure is an already written SQL statement that is saved in the database. Advantage Reduce roundtrips across the network Can make security easier to manage Are precompiled

17 STORED PROCEDURES - SQL How to run a stored procedures exec usp_displayallusers The SQL language inside the stored procedure SELECT * FROM USERLIST How to start with writing stored procedure A database management system A database built inside the database management system stem A text editor

18 FIRST STORED PROCEDURE /* Name: usp_displayallusers Description: displays all records and columns in USERLIST table Author: Tom O Neill Modification Log: Change Description Date Changed By Created procedure 7/15/2003 Tom O Neill */ CREATE PROCEDURE usp_displayallusers AS SELECT * FROM USERLIST

19 INPUT VARIABLES Input variables are essentially "storage" for data that you want to pass to your stored procedure. Global and local Declare at the top of the

20 INSERT CREATE PROCEDURE varchar(50) AS INSERT INTO USERLIST (login, pswd, f_name, l_name, address_1, address_2, city, state, zipcode, @ ) exec usp_adduser 'dnelson', 'dean2003', 'Dean', 'Nelson', '200 Berkeley Street', ' ', 'Boston', 'MA', '02116',

21 UPDATE CREATE PROCEDURE varchar(50) AS UPDATE USERLIST SET WHERE exec usp adduser 1010,'dnelson', 'dean2003', 'Dean', 'Nelson', '200 Berkeley exec usp_adduser 1010, dnelson, dean2003, Dean, Nelson, 200 Berkeley Street', ' ', 'Boston', 'MA', '02116',

22 PASS DATA TO A SELECT STORED PROCEDURE Steps Create header record Create stored procedure name and declare variables Create the rest of your stored procedure /* Name: usp_finduser Description: find a user Author: Tom O Neill Modification Log: Change Description Date Changed By Created procedure 7/15/2003 Tom O Neill */ */ exec usp_finduser 1 CREATE PROCEDURE int AS SELECT * FROM USERLIST WHERE usr_id=@usr_id

Java Database Connectivity (JDBC) 25.1 What is JDBC?

PART 25 Java Database Connectivity (JDBC) 25.1 What is JDBC? JDBC stands for Java Database Connectivity, which is a standard Java API for database-independent connectivity between the Java programming