Java sql delete row

Question

Hello I am trying to delete a row from my database. I am getting no errors but it is doing nothing, any help or advice would be great!

public static void DeleteRow(String name) {
    try {  
        Class.forName("com.mysql.jdbc.Driver");
        Connection connection = DriverManager.getConnection(url, username, password);

        PreparedStatement st = connection.prepareStatement("DELETE FROM Table WHERE name = " + name + ";");
        st.executeUpdate();
    } catch(Exception e) {
        System.out.println(e);
    }
}

What do you expect it to do?

Sotirios Delimanolis
– Sotirios Delimanolis

2014-02-04 04:13:42 +00:00
Commented Feb 4, 2014 at 4:13 — Sotirios Delimanolis
– Sotirios Delimanolis, Commented Feb 4, 2014 at 4:13

Miss Chanandler Bong · Accepted Answer · 2019-12-06 10:41:11Z

22

I guess name is a varchar type in DB so do like this

PreparedStatement st = connection.prepareStatement("DELETE FROM Table WHERE name = '" + name + "';");

enclose name within single quotes '

Also this is not the way you are using is not the proper way of using Preparedstatement

Us the following way:

PreparedStatement st = connection.prepareStatement("DELETE FROM Table WHERE name = ?");
st.setString(1,name);
st.executeUpdate(); 

// your full code after Proper PreparedStatement

public static void DeleteRow(String name) {
    try {  
        Class.forName("com.mysql.jdbc.Driver");
        Connection connection = DriverManager.getConnection(url, username, password);
        PreparedStatement st = connection.prepareStatement("DELETE FROM Table WHERE name = ?");
        st.setString(1,name);
        st.executeUpdate(); 
    } catch(Exception e) {
        System.out.println(e);
    }
}

edited Dec 6, 2019 at 10:41

Miss Chanandler Bong

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answered Feb 4, 2014 at 4:14

SpringLearner

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4 Comments

SpringLearner Over a year ago

@jeremyjjbrown no need to escape single quotes

user3268379 Over a year ago

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'Table WHERE name = 'UserTest''

SpringLearner Over a year ago

@user3268379 what is your table name? Table is a reserved keyword in mysql

SpringLearner Over a year ago

@jeremyjjbrown yes thats why I mentioned that this is not the proper way of preparedstament and also I have suggested how to do

jeremyjjbrown · Accepted Answer · 2014-02-04 04:28:30Z

2

You should never create a SQL statement in Java with String concatenation, it will be vulnerable to sql injection. Please do it this way.

String selectSQL = "DELETE FROM Table WHERE name = ?";
connection.prepareStatement(selectSQL);
preparedStatement.setString(1, name);

edited Feb 4, 2014 at 4:28

answered Feb 4, 2014 at 4:21

jeremyjjbrown

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Comments

Manash Ranjan Dakua · Accepted Answer · 2016-11-18 10:11:04Z

1

          Class.forName("oracle.jdbc.driver.OracleDriver");
          Connection con = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:XE", "MANASH_APPN","MANASH");
          PreparedStatement ps = con.prepareStatement("delete from EMP21 where empid = ?");
           ps.setInt(1,90);
           ps.executeUpdate();
          con.commit();
          System.out.println("Records Delete Successfully....");
         con.close();

answered Nov 18, 2016 at 10:11

Manash Ranjan Dakua

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Comments

wrecklez · Accepted Answer · 2014-06-18 06:07:27Z

0

try this bro. use Statement

Statement stmt = connection.createStatement();
String SQL = "DELETE FROM Table WHERE name = '"+name+"'";
stmt.executeUpdate(SQL);

answered Jun 18, 2014 at 6:07

wrecklez

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Comments

Miss Chanandler Bong · Accepted Answer · 2019-12-06 10:38:50Z

0

Every open connection must be closed, or it won't get implemented and no errors will be displayed. First learned lesson.

public static void DeleteRow(String name) {
    try {  
        Class.forName("com.mysql.jdbc.Driver");
        Connection connection = DriverManager.getConnection(url, username, password);

        PreparedStatement st = connection.prepareStatement("DELETE FROM Table WHERE name = " + name + ";");
        st.executeUpdate(); 
        connection.close();
    } catch(Exception e) {
        System.out.println(e);
    }
}

Hope this helps

edited Dec 6, 2019 at 10:38

Miss Chanandler Bong

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answered Feb 4, 2014 at 4:17

Sudharsun

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1 Comment

jeremyjjbrown Over a year ago

Your code is vulnerable to SQl injection. owasp.org/index.php/Preventing_SQL_Injection_in_Java

Asif alam · Accepted Answer · 2015-11-25 21:08:46Z

-1

this will work String del="DELETE FROM table WHERE name =('" + name + "')";

:)

answered Nov 25, 2015 at 21:08

Asif alam

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