Resultset not open. Verify Autocommit is OFF. Apache Debry

问题

I am using apache derby for my database. I am able to perform inserts into the database. The following is the excerpt from the code that attempts to display the contents of my only table 'MAINTAB'. The instance of java.sql.Connection is 'dbconn'.

    ResultSet word;

    Statement query;

    String getData="SELECT THEWORD FROM MAINTAB";
    try{
        System.out.println(dbconn.getAutoCommit());
        query = dbconn.createStatement();
        word = query.executeQuery(getData);
        query.close();

        dbconn.setAutoCommit(false);
        System.out.println(dbconn.getAutoCommit());

        for(;word.next();)
            System.out.println(word.getString(1));

    }catch(Throwable e){
        System.out.println("Table fetch failed or result data failed");}

And the following is the output.

org.apache.derby.jdbc.EmbeddedDriver loaded.
Database testDB connected
true
false
Table fetch failed or result data failed

---SQLException Caught---

SQLState:   XCL16
Severity: 20000
Message:  ResultSet not open. Operation 'getString' not permitted. Verify that autocommit is OFF.
java.sql.SQLException: ResultSet not open. Operation 'getString' not permitted. Verify that autocommit is OFF.
    at org.apache.derby.impl.jdbc.SQLExceptionFactory40.getSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.Util.newEmbedSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.Util.newEmbedSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.Util.generateCsSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedConnection.newSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.ConnectionChild.newSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedResultSet.checkIfClosed(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedResultSet.getString(Unknown Source)
Closed connection
    at test.ShowData.main(ShowData.java:30)
Caused by: java.sql.SQLException: ResultSet not open. Operation 'getString' not permitted. Verify that autocommit is OFF.
    at org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.SQLExceptionFactory40.wrapArgsForTransportAcrossDRDA(



Unknown Source)
    ... 9 more
Database shut down normally

When, it first asked to verify if AUTOCOMMIT is OFF, I have found from the Derby Documentation that AUTOCOMMIT is turned ON by default to any connection. So, I've turned it off using dbconn.setAutoCommit(false). Still, the error is thrown.

The output before the error explains that the result set was fetched without any error. Also, please note that the same error is thrown even if I do not set the AutoCommit to false. Between, I am running derby on eclipse.

回答1:

The problem is that you have closed your query before reading your resultset. Closing the query, closes the resultset, hence why you get the "ResultSet not open" error. You should close the query right at the end, in a finally block:

ResultSet word;

Statement query=null;

String getData="SELECT THEWORD FROM MAINTAB";
try{
    System.out.println(dbconn.getAutoCommit());
    query = dbconn.createStatement();
    word = query.executeQuery(getData);


    dbconn.setAutoCommit(false);
    System.out.println(dbconn.getAutoCommit());

    for(;word.next();)
        System.out.println(word.getString(1));

}catch(Throwable e){
    System.out.println("Table fetch failed or result data failed");
} finally{
    if(query!=null) {
        try {
             query.close();
        }
        catch(SQLException ex) {
              System.out.println("Could not close query");
        }
   }
}

回答2:

for me, it was the Connection object that got closed. so next time think about using your existing Connection object.

instead, I Use this everytime I make a new Query.

 private Connection getConnect() {
    try {
        return DriverManager.getConnection(Utils.getDatabaseConnection(), null);
    } catch (SQLException e) {
        e.printStackTrace();
        return null;
    }
}

and then do whatever with null check for ex.

getConnect().createStatement();

回答3:

You can do this by creating another statement variable initializing it with con.createStatement();

Statement stmt = con.createStatement();
Statement stmt2 = con.createStatement();
stmt.executeQuery(" your first query goes here ");
stmt2.executeQuery("your second query goes here");

Execute second query with second Statement variable. A solution for beginners.

来源：https://stackoverflow.com/questions/4049705/resultset-not-open-verify-autocommit-is-off-apache-debry

标签

java

sql

derby