使用JDBC的Mysql中的更新查询问题

Question

1. see the screenshots
2. see the 2nd screenshot
3. see the 3rd screenshot

Okay so I am building a project on java and mysql, I am stuck at this point that I have to update a data which is in MySql but from my java gui application, I've executed that update command from MySql command line client

update user set bldu = 50 where userid = 1001;

and it's working perfectly fine there but from my java application on clicking on assigned jbutton it says:

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 'userid= 1001' at line 1

Please help me..!

Answer 1

String query = "update user SET bldu = " + bldut + " WHERE userid = " + uid + ";";

使用此查询代替您的旧查询可能会对您有所帮助。

Answer 2

In your first screenshot you must add a space before WHERE clause:

String query = "UPDATE user SET bdlu = " + bldut + "WHERE userid = " + uid + ";";

So your query will be interpretated as:

UPDATE user SET bdlu = 50WHERE userid = 1001

So you'll raise a syntax error.

Then you'll have the following query:

String query = "UPDATE user SET bdlu = " + bldut + " WHERE userid = " + uid + ";";

Answer 3

Try this snippet in your code.

String query = "update user SET bldu = " + bldut + " WHERE userid = " + uid + ";";
Statement = con.prepareStatement(query);
Statement.executeUpdate();

by looking at your code you cannot store results of update query in resultSet the executeUpdate() only return 0 or 1 for success and failure of Update.

Answer 4

Okay i guys i have figured out something that it is working i mean this program is updating the data stored in mysql from netbeans via jdbc but it won't stop showing that error message like:

"Can not issue data manipulation statements with executeQuery()"

everytime i click one that assigned jButton..! but i checked the database the value i want to change is being changed but then why it is showing this error..?

Answer 5

Please use this code in your java file, do changes according to your file. your issue is you are using the same query in a result set that already uses for the update

Connection conn = DriverManager.getConnection( "jdbc:mysql://localhost:3306/bdb", "root", "root");

try {

    String query = "update user SET bldu = " + bldut+ " WHERE userid = " + uid + ";";           
    // create the java mysql update preparedstatement
    Class.forName("com.mysql.jdbc.Driver").newInstance();

    PreparedStatement preparedStmt = conn.prepareStatement(query);
    preparedStmt.executeUpdate();

    query = "select * from user  WHERE userid = " + uid +";";
    ResultSet rs = stmt.executeQuery(query);
    // STEP 5: Extract data from result set
    while (rs.next()) {
        // Retrieve by column name
        String userid = rs.getString("userid");
        String userfname = rs.getString("userfname");
        // all your column
        // Display values
        System.out.print("userid: " + userid);
    }
    // STEP 6: Clean-up environment
    rs.close();
    stmt.close();
    conn.close();
} catch (Exception e) {
    System.err.println("Got an exception! ");
    System.err.println(e.getMessage());
} finally {
    // finally block used to close resources
    try {
        if (conn != null)
            conn.close();
    } catch (SQLException se) {
        se.printStackTrace();
    }// end finally try
}// end try