Retrieve id of record just inserted into a Java DB (Derby) database

Question

I am connecting to a Java DB database with JDBC and want to retrieve the id (which is on auto increment) of the last record inserted.

I see this is a common question, but I see solutions using for example MS SQL Server, what is the equivalent for Java DB?

Answer 1

No need to use a DBMS specific SQL for that.

That's what getGeneratedKeys() is for.

When preparing your statement you pass the name(s) of the auto-generated columns which you can then retrieve using getGeneratedKeys()

PreparedStatement pstmt = connection.prepareStatement(
     "insert into some_table (col1, col2, ..) values (....)", 
      new String[] { "ID_COLUMN"} ); 

pstmt.executeUpdate();

ResultSet rs = pstmt.getGeneratedKeys(); // will return the ID in ID_COLUMN

Note that column names are case sensitive in this case (in Derby and many other DBMS).
new String[] { "ID_COLUMN"} is something different than new String[] { "id_column"}

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Alternatively you can also use:

connection.prepareStatement("INSERT ...", PreparedStatement.RETURN_GENERATED_KEYS);

Answer 2

You may be able to get what you're looking for using the IDENTITY_VAL_LOCAL function. (Derby Reference)

This function is supposed to return "the most recently assigned value of an identity column for a connection, where the assignment occurred as a result of a single row INSERT statement using a VALUES clause."

It's worth noting that this function will return DECIMAL(31,0), regardless of the actual data type of the corresponding identity column.

Also, this only works for single row inserts that contain a VALUES clause.