Proper SQL Delete statement

[Rook]

I would like to know what would be the proper SQL statement to delete something.

So far I have

String overall=request.getParameter ("overall");

Connection=Connection.connection(generic connection not the problem)
String sql="select from name where overall="+overall;
connection.executeQuery(sql);

This will run it just wont delete anything.

[doWhile]

Do not use executeQuery for operations like this - this method is to perform database Queries. To perform updates, use executeUpdate or execute

[DarrylBurke]

I would like to know what would be the proper SQL statement to delete something.

Apart from what doWhile has already pointed out -- Click here.

db

[Tolls]

Don't do JDBC until you know SQL.

That's Rule 1.

[Rook]

Apart from what doWhile has already pointed out -- Click here.

db

I did do that it still doesn't work I come here and for your experience not your smartcomments.

[Rook]

Do not use executeQuery for operations like this - this method is to perform database Queries. To perform updates, use executeUpdate or execute

I have done this and the variable I pass through is an invalid identifier.

[Tolls]

Come on, the query you posted above is a SELECT...it's not even a DELETE.

So do as I suggested and learn SQL.
We're on a teaching environment, at least not to that extent.

[Rook]

Come on, the query you posted above is a SELECT...it's not even a DELETE.

So do as I suggested and learn SQL.
We're on a teaching environment, at least not to that extent.

I posted the wrong page the select goes to a result set and then I have a link that forwards the information I know sql unions joins etc who cares I just dont know why the statement keeps kicking me back

String naming=request.getParameter ("naming");
String message="";

String sql="delete from name where overall="+naming;
connection.executeUpdate(sql);

[Tolls]

You would do better to post actual code.
That code won't have a hope in compiling as a Connection object does not have any sort of sql execution methods.

Next, you would also do well to explain your problem, because I can't tell whether it's a delete you're having problems with or a select or what.
That would include any exceptions, including full stack traces.

[Rook]

You would do better to post actual code.
That code won't have a hope in compiling as a Connection object does not have any sort of sql execution methods.

Next, you would also do well to explain your problem, because I can't tell whether it's a delete you're having problems with or a select or what.
That would include any exceptions, including full stack traces.

Page 1
String naming=request.getParameter ("naming");
String message1=request.getParameter("message1");
String message="";

JspConnection connection = new JspConnection(this);

String sql="select * from name";
ResultSet result=connection.executeQuery(sql);
while(result.next())
{
%>
<%=result.getString("overall")%>
<a href="deleting.jsp?name=<%=result.getString("overa ll")%>">Delete</a>
<%
}
connection.close(); %>
Page 2
<%


String naming=request.getParameter ("naming");
String message="";

JspConnection connection = new JspConnection(this);
{


String sql="delete from name where overall="+naming;
connection.executeUpdate(sql);
connection.close();
}
//try
//{


//}
//catch (SQLException sqlex)
//{
//message="ERROR : "+sqlex.getMessage();
//}


%>

<a href="tesing.jsp">Back"</a>

no stack errors...just wont delete..I made this 2 page item because I am working osmething that doesn't want to add or delete as well. It points to the same database. The connection is controlled by the web inf file.

[Tolls]

What on earth is a JspConnection?

[Rook]

What on earth is a JspConnection?

It is my connection statement controlled by the web inf. It is essentially a class file.

this statment pulls it in...<%@ page import="**.***.***.* ,**.***.***.database.*,java.sql.*,***.***.***.***. *" %>

this is the url in the web inf

(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=***) (HOST=**-oracle-**.**.**.**)(PORT=***)))(CONNECT_DATA=(SID=**)(SER VER=****)))

[Tolls]

But it's not standard...so how can we comment?
How can we see whether it is logging any exceptions?

[Rook]

But it's not standard...so how can we comment?
How can we see whether it is logging any exceptions?

The only exceptions this jspconnection will give is invalid username invalid password invalid url all it handles is the connection. I have had problems correcting this the lead proggrammer says it is connecting to the data base now. What would you want from the class file? Tomcat is not throwing any errors.

This simpliest way to explain it is that it is standered. It is what you would put in to a jsp. instead they made it all a generic class. so 20 lines go down to 1.

[Tolls]

So...what's your problem?
(Apart from writing business logic into a JSP page, of course, and not using PreparedStatements).

Something is either eating an exception, or the code is working and there's nothing to delete where "overall = naming".

Neither situation I can comment on as there is no code there.

[Rook]

From what is written here why would the delete statement not be deleting from the database? Am I missing something in my sql commands? here I will make it throw an error...

[Tolls]

Assuming the "overall" column is a NUMBER of some sort and naming (though a String) is also a number then that SQL is OK.
If it wasn't legal then it would throw an exception when you executed it.

As to whether it should actually delete anything, have you tried to run it against the db directly through SQLPlus (since it looks like you have an Oracle db there)?
Print out that SQL command so you can be certain you are doing the same as your code above.

[Rook]

Overall columns are string based not number based.Checking on sql. This is my issue lol...Need someone with much greater experience than me. The tables I am using have been resurrected from the dead as well. They havent been used in over 2 years I dont think that is a problem. The tables that I am calling from right now though has been made 2 days ago.

Main thing here is that delete from name where overall='oom' is different from "delete from name where overall="+naming

this .jsp little program was giving me invalid identifier issues. also it doesn't like the +naming it mans ADDING to tomcat

[Tolls]

If that column is a VARCHAR then that delete statement will throw a SQL exception.
No two ways about it.
DELETE FROM table_name WHERE varchar_field = something
will throw an exception since there's no quotes around that text.

If you are not getting an exception then your framework leaves a lot to be desired.

[Rook]

Should I change the value of it to something besides varchar? Could you post what the sql format should be in .jsp format? This is what I get when I put it in double qoutes.

I did not design the framework.

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: An exception occurred processing JSP page /deleting.jsp at line 14

11:
12:
13: String sql="delete from name where overall="+"naming";
14: connection.executeUpdate(sql);
15: connection.close();
16: }
17: //try


Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handle JspException(JspServletWrapper.java:519)
org.apache.jasper.servlet.JspServletWrapper.servic e(JspServletWrapper.java:410)
org.apache.jasper.servlet.JspServlet.serviceJspFil e(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspSe rvlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet .java:717)
edu.wayne.med.sso.filters.CookieCheckFilter.doFilt er(CookieCheckFilter.java:142)

root cause

javax.servlet.ServletException: java.sql.SQLException: ORA-00904: "NAMING": invalid identifier

org.apache.jasper.runtime.PageContextImpl.doHandle PageException(PageContextImpl.java:865)
org.apache.jasper.runtime.PageContextImpl.handlePa geException(PageContextImpl.java:794)
org.apache.jsp.deleting_jsp._jspService(deleting_j sp.java:93)
org.apache.jasper.runtime.HttpJspBase.service(Http JspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet .java:717)
org.apache.jasper.servlet.JspServletWrapper.servic e(JspServletWrapper.java:386)
org.apache.jasper.servlet.JspServlet.serviceJspFil e(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspSe rvlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet .java:717)
edu.wayne.med.sso.filters.CookieCheckFilter.doFilt er(CookieCheckFilter.java:142)

root cause

java.sql.SQLException: ORA-00904: "NAMING": invalid identifier

oracle.jdbc.dbaccess.DBError.throwSqlException(DBE rror.java:168)
oracle.jdbc.ttc7.TTIoer.processError(TTIoer.java:2 08)
oracle.jdbc.ttc7.Oall7.receive(Oall7.java:543)
oracle.jdbc.ttc7.TTC7Protocol.doOall7(TTC7Protocol .java:1405)
oracle.jdbc.ttc7.TTC7Protocol.parseExecuteFetch(TT C7Protocol.java:822)
oracle.jdbc.driver.OracleStatement.executeNonQuery (OracleStatement.java:1446)
oracle.jdbc.driver.OracleStatement.doExecuteOther( OracleStatement.java:1371)
oracle.jdbc.driver.OracleStatement.doExecuteWithTi meout(OracleStatement.java:1900)
oracle.jdbc.driver.OracleStatement.executeUpdate(O racleStatement.java:693)
edu.wayne.med.database.GenericConnection.executeUp date(GenericConnection.java:153)
edu.wayne.med.database.GenericConnection.executeUp date(GenericConnection.java:146)
org.apache.jsp.deleting_jsp._jspService(deleting_j sp.java:70)
org.apache.jasper.runtime.HttpJspBase.service(Http JspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet .java:717)
org.apache.jasper.servlet.JspServletWrapper.servic e(JspServletWrapper.java:386)
org.apache.jasper.servlet.JspServlet.serviceJspFil e(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspSe rvlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet .java:717)
edu.wayne.med.sso.filters.CookieCheckFilter.doFilt er(CookieCheckFilter.java:142)