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JSP for mySQL to Oracle

I have a small program that is written using JSP using mySQL at the backend (development) and I am thinking to move it to Oracle (production). There are a few conversion issues and I appreciate your input and suggestions:

1. In mySQL there is auto_increment function but not in Oracle 9i. In my JSP sql (that uses mySQL) I could have just use

insert into t_emp (id, name) value ('', 'Joe Black');

In oracle I uses sequence and the sql looks like:

insert into t_emp values (emp_seq.nextval, 'Joe Black');

How could I use just 1 type of sql for both databases?

2. If I use NOW() in the DATETIME in mySQL in some INSERT statement, what should I replace with in Oracle? sysdate seems to be doing the equivalent.

My real questions is, using JSP, how could I program in such a way that my program is independent of the database at the backend?

Thank you.

ASKER CERTIFIED SOLUTION

jarasa

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Tuan_Jean

ASKER

Thank you.

jarasa

Hi Tuan_Jean.
Did you solve the problem as I recomended you?
If you did I wonder why you assigned me a C grade instead an A grade.
regards
Javier.

Tuan_Jean

ASKER

Javier,

I understand the method you recommended are working but didn't use it as this makes the code very complex as each sql statement will have to had a switch.

However, I am not sure how the Grade C comes into the picture. I am happy to assign grade A. How do I do it?

jarasa

HI Tuan_Jean.

Actually there is a way that you could do it without a switch, if you place a session variable with the DB used onces you start the application you could have a constants file with all your querys for the different DataBase and use them as needed compounding them at runtime on the JSP, somethin like this.

constants.java
public class Constants
{

public Constants()
{
}

public static final String [] ORACLE = {"ORACLE SQL 1","ORACLE SQL 2"};
public static final String [] mySQL = {"mySQL SQL 1","mySQL SQL 2"};

public String get(String s, int n) {
      String p;
// You can make a switch here if you have more than 2 DBs
      if(s.equals("ORACLE"))
            p = this.ORACLE[n];
      else
            p = this.mySQL[n];
      return p;

}
}

access.jsp
<%@ page import="Constants" %>
<%
session.putValue("DB", "ORACLE"); // Obviously you must put this in the login jsp
Constants c = new Constants();
String sql = c.get((String) session.getAttribute("DB"),0);
......
%>
<html>
<head>
<title>Documento sin título</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>

<body>
<%=sql%>
</body>
</html>

About the A grade I thisk you shoud just post a comment to the sdministrators saying that you want the Grade changed for this question from C to A.

regards.
Javier

Tuan_Jean

ASKER

Javier. Thank you again.

Tuan_Jean

ASKER

Dear Administrator, I am very please with the answer Javier posted. Could you please change the grade from C to A. Thank you.