SQL & Database: Selecting & Deleting a record

[08butoryr]

Can someone please tell me what's wrong with this instruction:

String sql = "SELECT * FROM tblStudent WHERE Student Name = Samuel";

...And this one:

String input = JOptionPane.showInputDialog("Who do you want to delete:");
String sql = "DELETE * FROM tblStudent WHERE Student Name = " + input;

[madhoriya22]

Can someone please tell me what's wrong with this instruction:

String sql = "SELECT * FROM tblStudent WHERE Student Name = Samuel";

...And this one:

String input = JOptionPane.showInputDialog("Who do you want to delete:");
String sql = "DELETE * FROM tblStudent WHERE Student Name = " + input;

Hi,
Is "Student Name" is column name in ur table ?

[r035198x]

Can someone please tell me what's wrong with this instruction:

String sql = "SELECT * FROM tblStudent WHERE Student Name = Samuel";

...And this one:

String input = JOptionPane.showInputDialog("Who do you want to delete:");
String sql = "DELETE * FROM tblStudent WHERE Student Name = " + input;

Which database are you using?
The first statement should have quotes around Samuel if name is of type varchar or varchar2 depending on your database.
Your second statement should say delete from not delete * from.

[08butoryr]

Hi,
Is "Student Name" is column name in ur table ?

Firstly, thank you very much for responding to my problem. "Student Name" is indeed one of the column names in my table.

[08butoryr]

Which database are you using?
The first statement should have quotes around Samuel if name is of type varchar or varchar2 depending on your database.
Your second statement should say delete from not delete * from.

Thanks also for responding. The database I am using is called "School". How do I tell if the name is of type varchar or varchar2? Do I check directly in the database?

[r035198x]

Thanks also for responding. The database I am using is called "School". How do I tell if the name is of type varchar or varchar2? Do I check directly in the database?

I don't mean the name of your database in that sense. I mean is it MySQL, Oracle, Access, e.t.c. The structure of the sql depends on the database.

[08butoryr]

I don't mean the name of your database in that sense. I mean is it MySQL, Oracle, Access, e.t.c. The structure of the sql depends on the database.

It is Access. But in fact I've been working on this the whole day and I've virtually completed the whole thing. I have just 2 small problems left:
1. In the search method, I need to figure out how to display "Name not found" when the user inputs a name that's not in the database. I tried using the following code but it didn't work:

boolean inputRepeatedly = true;
while (inputRepeatedly = true)
{
try
{    
String input1 = JOptionPane.showInputDialog("Please enter student's name");
if (input1.length() == 0)
{
inputRepeatedly = false;
}

2. How do you exit a submenu? i.e. The main menu pops up, user selects 'A) Insert name', user is repeatedly prompted to insert new records in the table until he wishes to cancel. I tried using the following code but it didn't work:

String input = JOptionPane.showInputDialog("Which name are you searching for?");
rs = set.executeQuery("SELECT * FROM tblStudent WHERE StudentName = " + "'" + input + "'"); 
 
while (rs.next())
{
name = rs.getString("StudentName");
if (name.equals(input)
{
System.out.println(name + " is present in the table");
}
else
{
System.out.println(name + " is not present");
}

After these small problems are solved, I am completely done so thanks in abundance for helping.

[mrindia]

Can someone please tell me what's wrong with this instruction:

String sql = "SELECT * FROM tblStudent WHERE Student Name = Samuel";

...And this one:

String input = JOptionPane.showInputDialog("Who do you want to delete:");
String sql = "DELETE * FROM tblStudent WHERE Student Name = " + input;

Hi,
Some one gave good response. I am newly added in this group...

so u better to use string.Format method .. here we can avoid collisions

if u want assign any parameter to your query so better to create one format string based on that no need to take care of complicated built query

string.Format(" Select statements from table where col =place holer",col1,col2,...)

Ex:

String.Format("Select * FROM tblStudent WHERE StudentName ='{0}' ",StudentName);

SeleStat=String.Format("DELETE * FROM tblStudent WHERE StudentName = '{0}'",input);


write like this ..if column is string u have specify place holder in string otherwise no need strings(Invited commas)...

Note: columns should not take any gaps


ok

if it is helpful take it

otherwise ...take just kidding
bye

[08butoryr]

Hi,
Some one gave good response. I am newly added in this group...

so u better to use string.Format method .. here we can avoid collisions

if u want assign any parameter to your query so better to create one format string based on that no need to take care of complicated built query

string.Format(" Select statements from table where col =place holer",col1,col2,...)

Ex:

String.Format("Select * FROM tblStudent WHERE StudentName ='{0}' ",StudentName);

SeleStat=String.Format("DELETE * FROM tblStudent WHERE StudentName = '{0}'",input);


write like this ..if column is string u have specify place holder in string otherwise no need strings(Invited commas)...

Note: columns should not take any gaps


ok

if it is helpful take it

otherwise ...take just kidding
bye

Thank you very much - I will definitely take it!

[r035198x]

Have I suggest PreparedStatements yet?