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Database Processing with JSP

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;.

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Database Processing with JSP

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  1. Database Processing with JSP ISYS 350

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

  3. Create a CID ListBox

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

  5. 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 + "'";

  6. 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’);

  7. 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 + "')";

  8. Creating a Java DB (Derby) Database with NetBeans • Tutorial: • http://netbeans.org/kb/docs/ide/java-db.html#starting

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

  10. Connect or Delete a database: Right click database name

  11. Connected Database

  12. Creating a New Table: Open the App folder, and:1.Right click Tables and select create table2. Enter Table name3. Click Add column to define field

  13. Create a New Table • Table name: Customer • Fields: • CID: Type – CHAR with size 5; primary key • Cname: Type – CHAR with size 20 • City:Type – CHAR with size 20 • Rating: Type – CHAR with size 1

  14. To insert records to a table: • Right-click the table name and select View Data • From the record view window, click the Insert Record button:

  15. Database Processing with JSP • Must import java.sql using page directive: • <%@page import="java.sql.*" %> • Need a driver: • Java Derby database: • Example: • String DBUrl="jdbc:derby://localhost:1527/SalesDBJava";

  16. 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 + "'"; • ResultSetrs = 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 + "')"; intCount; Count=SQLStatement.executeUpdate(strSQL);

  17. 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.

  18. 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()

  19. Enter CID: HTML Form <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Insert title here</title> </head> <body> <form action="getCustomer.jsp" method="post"> <p>Enter CID: <input name="cid" type="text" size="20" maxlength="20" ></p> <input type="submit" value="Submit"> </form> </body> </html>

  20. Jdbc:derby demo: Accessing a Derby database SalesDBJava with username and password. Note: Using Derby, SQL stastement cannot end with “;” <% 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 + "'"; ResultSetrs = SQLStatement.executeQuery(strSQL); if (rs.next()) { Cname=rs.getString("CNAME"); City=rs.getString("CITY"); Rating=rs.getString("Rating"); rs.close(); %> Cname: <input type="text" name="name" size="20" value="<%=Cname%>"><br> City: <input type="text" name="city" size="20" value="<%=City%>"><br> Rating: <input type="text" name="rating" size="3" value="<%=Rating%>"><br> <% } else { out.println("Customer not exist!"); rs.close(); } } catch(SQLExceptione) { out.println("Something wrong"); out.println(e.getMessage()); } %>

  21. Derby demo:Populate a Listbox using a ResultSet <form name="cidForm" method ="post" action="getCustomer.jsp"> <p>Select CID:<select name="cid"></p> <% 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"; ResultSetrs = SQLStatement.executeQuery(strSQL); while (rs.next()) { myCid=rs.getString("cid"); out.println("<option value='" +myCid + "'>" + myCid + "</option>"); } } catch(SQLException e) { out.println(e.getMessage()); } %> </select> <input type="submit" value="GetCustomerData" name="btnSubmit" /> </form>

  22. 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"; ResultSetrs = SQLStatement.executeQuery(strSQL); %> <table border='1' width='400' cellspacing=1> <thead> <tr> <th>CID</th> <th>Cname</th> <th>City</th> <th>Rating</th> </tr> </thead> <tbody> <% while (rs.next()) { Cid=rs.getString("CID"); Cname=rs.getString("CNAME"); City=rs.getString("CITY"); Rating=rs.getString("Rating"); %> <tr> <td width='25%'><%=Cid%></td> <td width='25%'><%=Cname%></td> <td width='25%'><%=City%></td> <td width='25%'><%=Rating%></td> </tr> <% } rs.close(); } catch(SQLException e) { out.println(e.getMessage()); } %>

  23. 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 + "'"; ResultSetrs = SQLStatement.executeQuery(strSQL); if (rs.next()) { Cname=rs.getString("CNAME"); City=rs.getString("CITY"); Rating=rs.getString("Rating"); rs.close(); %> Cname: <input type="text" name="name" size="20" value="<%=Cname%>"><br> City: <input type="text" name="city" size="20" value="<%=City%>"><br> Rating: <input type="text" name="rating" size="3" value="<%=Rating%>"><br> <% } else { out.println("Customer not exist!"); rs.close(); } } catch(SQLException e) { out.println(e.getMessage()); } %>

  24. 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 + "')"; intCount; Count=SQLStatement.executeUpdate(strSQL); if (Count==1) out.println("Insertion sucessful"); } catch(SQLException e) { out.println(e.getMessage()); } %>

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