Special Edition Using Java™ 2 Enterprise Edition

Troubleshooting

Creating Tables

Q1:	Why won't the database let me create a primary key using a column that allows null values?
Some databases require the primary-key column to have a non-null value at all times. Although some databases might permit null values, the fact that the column is a primary key means that you can have at most one null value for that column in the table, because the primary key must be unique.
Q2:	Why does the database complain that my table already exists?
To create a new version of a table, you should first use the DROP TABLE command to delete the old version. Keep in mind, however, that DROP TABLE deletes all the data in the old table.
Q3:	Why won't the database let me create a table?
Some databases have security settings that ...