Database Processing with JSP ISYS 350

Example: Enter CID in a box and retrieve the customer record

Create a CID ListBox

SQL Select Command Select all records from a table: SELECT * FROM tableName; Select records meeting criteria: SELECT * FROM tableName WHERE criteria;

Creating a String Containing SQL Select Command Assuming the CID is entered in a HTML textbox named “cid” or selected from a HTML listbox named “cid”: String myCIDS, strSQL; myCid=request.getParameter("cid"); strSQL="select * from customer where cid='" + myCid + "'";

SQL Insert Command INSERT INTO tableName VALUES (field values separated by commas); Ex 1. Customer table with CID, CNAME, CITY, RATING. INSERT INTO CUSTOMER VALUES (‘C1’, ‘SMITH’, ‘SF’, ‘A’); Ex 2. Orders table with OID, OrderDate, CID, SalesPerson INSERT INTO ORDERS VALUES (‘O11’, #9/28/02#, ‘C1’, ‘Peter’);

Creating A String Containing SQL Insert Command myCid=request.getParameter("cid"); myCname=request.getParameter("cname"); myCity=request.getParameter("city"); myRating=request.getParameter("rating"); strSQL = "Insert into Customer values ('"; strSQL += myCid + "','" + myCname + "','"; strSQL += myCity + "','" + myRating + "')";

Creating a Java DB (Derby) Database with NetBeans Tutorial: – db.html#starting db.html#starting

Creating a Database: Right click Java DB and select Create Database Note: Username and password.

Connect or Delete a database: Right click database name

Connected Database

Creating a New Table: 1. Right click Tables and select create table 2. Enter Table name 3. Click Add column to define field

Database Processing with JSP Must import java.sql using page directive: – Need a driver: – JDBC-ODBC Bridge: The JDBC-ODBC Bridge allows applications written in the Java programming language to use with many existing ODBC drivers. – Note: JDBC-ODBC does not work if you have a Windows 7 64-bit system and 32-bit MS Access. – Example: String DBUrl="jdbc:odbc:MySalesDB"; – Java Derby database: – Example: String DBUrl="jdbc:derby://localhost:1527/SalesDBJava";

Define Database Objects Define connection object: – connection = DriverManager.getConnection(DBUrl); Define SQL Statement object: – Statement SQLStatement = connection.createStatement(); SQL Statement methods: – 1. executeQuery: This method executes SQL Select statement and create a resultset object: – Example: strSQL="select * from customer where cid='" + myCid + "'"; ResultSet rs = SQLStatement.executeQuery(strSQL); – 2. executeUpdate: This method executes SQL Insert, Delete and Update statement and returns the number of records affected by the statement. – Example: strSQL = "Insert into Customer values ('"; strSQL += myCid + "','" + myCname + "','"; strSQL += myCity + "','" + myRating + "')"; int Count; Count=SQLStatement.executeUpdate(strSQL);

JDBC ResultSet The rows that satisfy a particular query are called the result set. The number of rows returned in a result set can be zero or more. A user can access the data in a result set using a cursor one row at a time from top to bottom. A cursor can be thought of as a pointer to the rows of the result set that has the ability to keep track of which row is currently being accessed.

ResultSet Methods Next() : Returns true if the cursor is now positioned on a row and false if the cursor is positioned after the last row. previous() first() last()

HTML Form Enter CID: Insert title here Enter CID:

<% Connection connection = null; String DBUrl="jdbc:odbc:MyCustomer"; try { String myCid, strSQL, Cname, City, Rating; connection = DriverManager.getConnection(DBUrl); Statement SQLStatement = connection.createStatement(); myCid=request.getParameter("cid"); strSQL="select * from customer where cid='" + myCid + "'"; ResultSet rs = SQLStatement.executeQuery(strSQL); if (rs.next()) { Cname=rs.getString("CNAME"); City=rs.getString("CITY"); Rating=rs.getString("Rating"); rs.close(); %> Cname: "> City: "> Rating: "> <% } else { out.println("Customer not exist!"); rs.close(); } catch(SQLException e) { out.println("Something wrong"); out.println(e.getMessage()); } %> Jdbc:odbc demo: A DSN MyCustomer is defined for a SQL Server database.

Select CID: <% Connection connection = null; String DBUrl="jdbc:odbc:MyCustomer"; try { String myCid, strSQL; connection = DriverManager.getConnection(DBUrl); Statement SQLStatement = connection.createStatement(); strSQL="select cid from customer;"; ResultSet rs = SQLStatement.executeQuery(strSQL); while (rs.next()) { myCid=rs.getString("cid"); out.println(" " + myCid + " "); } catch(SQLException e) { out.println(e.getMessage()); } %> Populate a Listbox using a ResultSet

Show Records in a Table <% Connection connection = null; String DBUrl="jdbc:odbc:MyCustomer"; try { String Cid, strSQL, Cname, City, Rating; connection = DriverManager.getConnection(DBUrl); Statement SQLStatement = connection.createStatement(); strSQL="select * from customer"; ResultSet rs = SQLStatement.executeQuery(strSQL); %> CID Cname City Rating <% while (rs.next()) { Cid=rs.getString("CID"); Cname=rs.getString("CNAME"); City=rs.getString("CITY"); Rating=rs.getString("Rating"); %> <% } rs.close(); } catch(SQLException e) { out.println(e.getMessage()); } %>

Insert a New Record <% Connection connection = null; String DBUrl="jdbc:odbc:MyCustomer"; try { String myCid, strSQL, myCname, myCity, myRating; connection = DriverManager.getConnection(DBUrl); Statement SQLStatement = connection.createStatement(); myCid=request.getParameter("cid"); myCname=request.getParameter("cname"); myCity=request.getParameter("city"); myRating=request.getParameter("rating"); strSQL = "Insert into Customer values ('"; strSQL += myCid + "','" + myCname + "','"; strSQL += myCity + "','" + myRating + "')"; int Count; Count=SQLStatement.executeUpdate(strSQL); if (Count==1) out.println("Insertion sucessful"); } catch(SQLException e) { out.println(e.getMessage()); } %>

<% Connection connection = null; String DBUrl="jdbc:derby://localhost:1527/SalesDBJava"; try { String myCid, strSQL, Cname, City, Rating; connection = DriverManager.getConnection(DBUrl,"dchao","dchao"); Statement SQLStatement = connection.createStatement(); myCid=request.getParameter("cid"); strSQL="select * from customer where cid='" + myCid + "'"; ResultSet rs = SQLStatement.executeQuery(strSQL); if (rs.next()) { Cname=rs.getString("CNAME"); City=rs.getString("CITY"); Rating=rs.getString("Rating"); rs.close(); %> Cname: "> City: "> Rating: "> <% } else { out.println("Customer not exist!"); rs.close(); } catch(SQLException e) { out.println("Something wrong"); out.println(e.getMessage()); } %> Jdbc:derby demo: Accessing a Derby database SalesDBJava with username and password. Note: Using Derby, SQL stastement cannot end with “;”

Select CID: <% Connection connection = null; String DBUrl="jdbc:derby://localhost:1527/SalesDBJava"; try { String myCid, strSQL; connection = DriverManager.getConnection(DBUrl,"dchao","dchao"); Statement SQLStatement = connection.createStatement(); strSQL="select cid from customer"; ResultSet rs = SQLStatement.executeQuery(strSQL); while (rs.next()) { myCid=rs.getString("cid"); out.println(" " + myCid + " "); } catch(SQLException e) { out.println(e.getMessage()); } %> Derby demo:Populate a Listbox using a ResultSet

Derby demo:Show Records in a Table <% Connection connection = null; String DBUrl="jdbc:derby://localhost:1527/SalesDBJava"; try { String Cid, strSQL, Cname, City, Rating; connection = DriverManager.getConnection(DBUrl,"dchao","dchao"); Statement SQLStatement = connection.createStatement(); strSQL="select * from customer"; ResultSet rs = SQLStatement.executeQuery(strSQL); %> CID Cname City Rating <% while (rs.next()) { Cid=rs.getString("CID"); Cname=rs.getString("CNAME"); City=rs.getString("CITY"); Rating=rs.getString("Rating"); %> <% } rs.close(); } catch(SQLException e) { out.println(e.getMessage()); } %>

Jdbc:odbc: Reading Cookie and Customer Record <% try{ String myCid, strSQL, Cname, City, Rating; Cookie[] cookies = request.getCookies(); myCid=cookies[0].getValue(); Connection connection = null; String DBUrl="jdbc:odbc:MyCustomer"; connection = DriverManager.getConnection(DBUrl); Statement SQLStatement = connection.createStatement(); strSQL="select * from customer where cid='" + myCid + "'"; ResultSet rs = SQLStatement.executeQuery(strSQL); if (rs.next()) { Cname=rs.getString("CNAME"); City=rs.getString("CITY"); Rating=rs.getString("Rating"); rs.close(); %> Cname: "> City: "> Rating: "> <% } else { out.println("Customer not exist!"); rs.close(); } catch(SQLException e) { out.println(e.getMessage()); } %>

Show Customer/Orders 1. A HTML form with CID listbox 2. Show selected customer’s record and related records.

<% Connection connection = null; String DBUrl="jdbc:odbc:MyCustomer"; try { String myCid, strSQL, Cname, City, Rating; String OID, SalesPerson; Date OrderDate; connection = DriverManager.getConnection(DBUrl); Statement SQLStatement = connection.createStatement(); myCid=request.getParameter("cid"); strSQL="select * from customer where cid='" + myCid + "'"; ResultSet rs = SQLStatement.executeQuery(strSQL); if (rs.next()) { Cname=rs.getString("CNAME"); City=rs.getString("CITY"); Rating=rs.getString("Rating"); rs.close(); %> Cname: "> City: "> Rating: ">

OID ODate SalesPerson <% Statement SQLStatementOrder = connection.createStatement(); strSQL="select * from orders where cid='" + myCid + "'"; ResultSet rsOrder = SQLStatementOrder.executeQuery(strSQL); while (rsOrder.next()) { OID=rsOrder.getString("OID"); OrderDate= rsOrder.getDate("ODate"); SalesPerson=rsOrder.getString("SalesPerson"); %> <% } rsOrder.close(); } else { out.println("Customer not exist!"); rs.close(); } catch(SQLException e) { out.println(e.getMessage());} %>