How to auto increment database column in Java derby?

3
votes

Here's the SQL I've tried so far to create the table

CREATE TABLE tblPosts (nId INTEGER PRIMARY KEY GENERATED ALWAYS AS IDENTITY,
strContent VARCHAR(140) NOT NULL,
strLink VARCHAR(200),
strImage VARCHAR(200));

using 

String sql = "INSERT INTO tblPosts VALUES ('" + textFieldContent.getText() + "', '" + 

textFieldLink.getText() + "', '" + textFieldImage.getText() + "')";

I get an error telling me I'm not providing the nId column value which I'm not but if the column auto-increments I'm not supposed to right?

I've also tried using the IDE to create the table on the database as described here

Alter a table column with auto increment by 1 in derby

Same response though. Any suggestions?

3
javasqlderbyauto-increment
I would specify the column names in your INSERT command. Also, I would post the actual error. - Steve Smith
@SteveSmith Thanks Steve. - luigivampa
Does that mean it worked? - Steve Smith
@SteveSmith Yup. :) - luigivampa

3 Answers

4
votes

You need to include Start with 1, Increment by 1 Like this

CREATE TABLE tblPosts (nId INTEGER PRIMARY KEY GENERATED ALWAYS AS IDENTITY(Start with 1, Increment by 1), 
strContent VARCHAR(140) NOT NULL, 
strLink VARCHAR(200)
1
votes

I would guess that since you're not specifying the column names in the SELECT, it is getting confused as to which columns the data should go in. I would specify the column names in your INSERT command.

0
votes

You need to set THAT auto_increment column to DEFAULT like this:

String sql = "INSERT INTO tblPosts VALUES ( DEFAULT, '" + textFieldContent.getText() + "', '" + 

textFieldLink.getText() + "', '" + textFieldImage.getText() + "')";