For Mysql queries or any database


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Thread: For Mysql queries or any database

  1. #1
    Join Date
    Aug 2005
    Posts
    41

    Question For Mysql queries or any database

    Hi everyone.

    I finally have a connection with Mysql and a simple java program. I can select and display everything in the database in the command line console. I can change values in the database if I hard wire them into the code everytime. But I have a GUI interface that I want to be able to type in some text and then press a button and the database value is changed to what I wrote in the text box.

    I have a JTextbox, where I want to get my text from and I have a JButton to press to execute the change. Am I doing it right so far?? I would like to take what ever is in the textbox and insert it into the databse. How can I acheive this? I tried to use a String variable in the java code and insert it into the query statment but that just gives me an error message when I hit the button to insert it into the database.

    This is a snippet of code:

    String v="12";
    st.executeUpdate("UPDATE male " +
    "SET age= v"+
    "WHERE fname='richard'"
    );


    I can understand that the statement sends a string to MySql and I want to insert a variable so it wouldn't work. How would you then make this work??

    airrazor

  2. #2
    Join Date
    Aug 2005
    Posts
    6
    hi arrazor.....

    i think inside the table male u hve declared age as int
    then
    try this..


    String v="12";
    st.executeUpdate("UPDATE male SET age='"+Integer.parseInt((String)v)+"'
    +"WHERE fname='richard'");

    here u hve declared v as String....but u hve to convert it into int before giving this value inside a sql query

    for that we use this

    Integer.parseInt((String)v)


  3. #3
    Join Date
    Oct 2005
    Posts
    1
    Please try:

    if the field age is char or varchar:

    String v="12";
    st.executeUpdate("UPDATE male SET age='" + v + "' WHERE fname='richard'");

    if the field age is int:

    String v="12";
    st.executeUpdate("UPDATE male SET age=" + Integer.parseInt((String)v) + " WHERE fname='richard'");
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  4. #4
    Join Date
    Aug 2005
    Posts
    41

    thanks for your help

    thanks mysqlautobackup and vsorc,
    you were great help. What you suggested worked and I am able to query the database. If i were to query the database for a date and time would I have to do the same thing? If so what syntax would I use?

  5. #5
    Join Date
    Aug 2005
    Posts
    41

    INSERT syntax

    Hey guys,
    to follow up on your helps, I have another question. Am I able to do this:

    st.executeQuery("INSERT INTO Male" +
    "VALUES ('"+Integer.parseInt((String)acc)+"'"+
    ",'"+char.parseInt((String)ident)+"'"+
    ",'"+Date.parseInt((String)birthday)+"'"+
    ",'"+Time.parseInt((String)tfrom)+"'"+
    ",'"+float.parseInt((String)feecost)+"');");

    The Integer works fine but i get an error message for the char "class expected". Do I need to import something? How do the time,date and float look?

  6. #6
    Join Date
    Oct 2005
    Location
    New Jersey
    Posts
    255
    Quote Originally Posted by airrazor
    Hey guys,
    to follow up on your helps, I have another question. Am I able to do this:

    st.executeQuery("INSERT INTO Male" +
    "VALUES ('"+Integer.parseInt((String)acc)+"'"+
    ",'"+char.parseInt((String)ident)+"'"+
    ",'"+Date.parseInt((String)birthday)+"'"+
    ",'"+Time.parseInt((String)tfrom)+"'"+
    ",'"+float.parseInt((String)feecost)+"');");

    The Integer works fine but i get an error message for the char "class expected". Do I need to import something? How do the time,date and float look?
    char is not a class and you cannot invoke methods on it. Same for float. Date and Time do not have parseInt() methods. Take a look at PreparedStatement instead of writing code in this manner. PreparedStatement will simpify your problems considerably.
    Happiness is good health and a bad memory.

  7. #7
    Join Date
    Oct 2005
    Posts
    6
    you may want to add more exist live connections to your application , try this tool :

    http://www.smartvi.com/sep.htm

    Regards

  8. #8
    Join Date
    Aug 2005
    Posts
    41

    Question what do you mean?

    Hi aniseed,
    What do you mean using PreparedStatement will help simplify my problem? Won't I still have to write the same code when I create the PreparedStatements? Including the formatting?

  9. #9
    Join Date
    Aug 2005
    Posts
    6
    hi


    in this u hve to use

    st.executeUpdate insted of st.executeQuery

    this will solve the problem

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