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Store serialized objects in MySQL

Hi!

I've been stuck with this one all afternoon and I'm in bit of a rush (it has to be done by tomorrow so the points are set accordingly :). I have two methods in a Week class, which implements serializable:

public byte[] toByteArray()
public static synchronized Week fromByteArray(byte[] bytearray)

toByteArray(), which works for sure, returns the serialized object as an array of bytes and fromByteArray should rebuild the object (don't know yet if it actually works).

The problem I have is when I try to write it to a mysql database. Here is the method which should perform the writing:

  public static synchronized void saveBaseWeek ( String userName, Week week ) {
    // Prepare a statement to insert binary data
    String sql = "";
    PreparedStatement pstmt = null;
    byte[] bytearray = null;
     
    bytearray = new byte[week.toByteArray().length];
    bytearray = week.toByteArray();

    //sql = "USE ?; INSERT INTO ? ( ?,?) VALUES ( ?,? );";
    sql = "USE " + Constants.APPLICATION.DATABASE.DATABASE_NAME + "; INSERT INTO " + Constants.APPLICATION.DATABASE.BASEWEEK_TABLE_NAME + " ( " + Constants.APPLICATION.DATABASE.USERNAME_COL_NAME + "," + Constants.APPLICATION.DATABASE.BASEWEEK_COL_NAME + " ) VALUES ( ?,? );";
    try {
      pstmt = myCon.prepareStatement(sql);
      // Set values for the prepared statement
      //pstmt.setString(1, Constants.APPLICATION.DATABASE.DATABASE_NAME);
      //pstmt.setString(2, Constants.APPLICATION.DATABASE.BASEWEEK_TABLE_NAME);
      //pstmt.setString(3, Constants.APPLICATION.DATABASE.BASEWEEK_COL_NAME);
      //pstmt.setString(4, Constants.APPLICATION.DATABASE.USERNAME_COL_NAME);
      pstmt.setString(1, userName);
      pstmt.setBytes (2, bytearray);
    } catch (Exception ex) {ex.printStackTrace();}

    // Insert the data
    try {
      pstmt.execute();
      pstmt.close();
    } catch (Exception ex) {ex.printStackTrace();}
   
  }
 

A part of the stacktrace thrown by pstmt.execute() reads

STACKTRACE >>>>>>
java.sql.SQLException: Syntax error or access violation: You have an error in your SQL syntax near '; INSERT INTO Baseweek ( Username,BaseweekObject ) VALUES ( 'r','’\0sr\08com.n' at line 1
     at org.gjt.mm.mysql.MysqlIO.sendCommand(MysqlIO.java:497)
     at org.gjt.mm.mysql.MysqlIO.sqlQueryDirect(MysqlIO.java:550)
     at org.gjt.mm.mysql.Connection.execSQL(Connection.java:885)
     at org.gjt.mm.mysql.PreparedStatement.execute(PreparedStatement.java:1093)
<<<<<< STACKTRACE


The table's description is:

mysql> describe baseweek;
+----------------+-------------+------+-----+---------+-------+
| Field          | Type        | Null | Key | Default | Extra |
+----------------+-------------+------+-----+---------+-------+
| BaseweekObject | blob        | YES  |     | NULL    |       |
| Username       | varchar(15) |      | PRI |         |       |
+----------------+-------------+------+-----+---------+-------+
2 rows in set (0.00 sec)

mysql>





Any suggestions on what I'm missing?


Regards,

Marko
0
_marko_
Asked:
_marko_
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1 Solution
 
girionisCommented:
 Can you set the database you use when you connect to the db server and then only send the INSERT statement to the db server? It might not like the ; in front of the INSERT statement.
0
 
_marko_Author Commented:
It worked!!! Unbelievable!!! I have used the USE-statement in other queries, but they have not been prepared statements so I didn't think it would make a difference.

Hehe, now I can go to the beach instead of having to do any more bug hunting :)


Thank you girionis very, very much!


Regards,

Marko
0
 
girionisCommented:
 You can never be sure with computers... One thing that is working fine in one machine might not work at all in another.

  Thank you for the points, I am glad I helped :-)

  P.s. Enjoy the beach.
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