Saving Records Using Java

Question

I am saving date logs every time a user logs in. Date logs will save a date in the record, but what I want is for there to be no duplicates. It will check if the record is already existing, and if yes it will not save the date. If the record does not yet exist it will save the date.

Here is my code:

 SimpleDateFormat dnow2 = new SimpleDateFormat("MMMMM dd, yyyy");

 ResultSet ds = MyDB.rsFetch("SELECT * FROM `date-logs` WHERE `Date` = '"+dnow.format(new java.util.Date())+"'");

 try {
   ds.next() ; 

   if (ds.getMetaData().getColumnCount() == 0) {
     MyDB.exSQL(  "INSERT INTO `date-logs` (`Date Code`, `Date`) " 
                + "VALUES ('"+dnow.format(new java.util.Date())+ "',"
                + "'"+dnow2.format(new java.util.Date())+"')");   
   }
 } catch (SQLException ex) {
   Logger.getLogger(FrmLogIn.class.getName()).log(Level.SEVERE, null, ex);
 }

if there existing record to the database it will not save anymore if. new record it will save. when i run this nothing happens can you help me — kelvzy
– kelvzy, Commented Feb 21, 2013 at 1:47
Have you checked if your SELECT query is working properly, i.e if it is actually returning any result. Looks like you are formatting your date as "MMMMM dd, yyyy" which evaluates to 'February 21, 2013'. Can you check if the query SELECT * FROM date-logs WHERE Date = 'February 21, 2013' is retriving any result. — Jayamohan
– Jayamohan, Commented Feb 21, 2013 at 2:49
all I just want to happen if the record is already existing it will not save anymore if, if new record it will save — kelvzy
– kelvzy, Commented Feb 21, 2013 at 3:30

kelvzy · Accepted Answer · 2013-02-21 03:37:35Z

1

Finally I got it !!!

 SimpleDateFormat dnow2 = new SimpleDateFormat("MMMMM dd, yyyy");

    ResultSet ds = MyDB.rsFetch("SELECT * FROM `date-logs` WHERE `Date Code` = '"+dnow.format(new java.util.Date())+"'");


  int resultsCounter = 0;  
    try {
        while(ds.next())  
        {  
        //procedure when results were returned  
        resultsCounter++;  
        }

        if (resultsCounter ==0)  
        {  

      MyDB.exSQL("INSERT INTO `date-logs` (`Date Code`, `Date`) VALUES ('"+dnow.format(new java.util.Date())+ "',"
                     + "'"+dnow2.format(new java.util.Date())+"')");
        }  
    } catch (SQLException ex) {
        Logger.getLogger(FrmLogIn.class.getName()).log(Level.SEVERE, null, ex);
    }

answered Feb 21, 2013 at 3:37

kelvzy

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jdevelop · Accepted Answer · 2013-02-21 01:12:20Z

0

I don't know which database abstraction stuff you're using, but you should update it to use prepared statements.

Next, you should use MySQL specific query, like:

insert into date logs ... on duplicate key ignore

make sure that Date is primary key. This kind of query will ignore inserts if the key already exists in the database.

answered Feb 21, 2013 at 1:12

jdevelop

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4 Comments

kelvzy Over a year ago

if I make that primary then when another user will login it will cause an error

jdevelop Over a year ago

According to your example, you are not storing any user-specific information in logs table, so it doesn't matter. If it does - you may use compound primary key on username and date columns.

kelvzy Over a year ago

MyDB.exSQL( "INSERT INTO date-logs (Date Code, Date) " + "VALUES ('"+dnow.format(new java.util.Date())+ "'," + "'"+dnow2.format(new java.util.Date())+"')");

kelvzy Over a year ago

date-log is in the other table so when one user will log in... this code will run

Chan · Accepted Answer · 2013-02-21 02:46:07Z

0

What you should be doing is to add another foreign key for user (make it primary as well) to the date-logs table. Even if you insert the same data twice it will ignore the query since the primary key already exists in the database.

answered Feb 21, 2013 at 2:46

Chan

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