Derby Database Table Column Name Format Inconsistent in Query

Question

When query a Derby database, I find out that for some tables I have to double quote the column name and use table name to qualify the column name, but for some other tables I d

Answer 1

Putting a tablename or column name in quotes, sometimes referred to by the jargon-y term "delimited identifiers" does two things:

1. Allows you to use words that are otherwise reserved keywords (e.g., naming a column "WHERE" or "SELECT")
2. Instructs the database system to process the name using case sensitive rules, rather than case-insensitive rules

So if you originally created "table3" with a CREATE TABLE statement that specified "table3" in double quotes like this, then you will forever after have to refer to it with the name in double quotes.

select * from table3

will be automatically processed by the database as if it was

select * from TABLE3

while

select * from "table3"

will successfully match the table you created as create table "table3"

See: http://db.apache.org/derby/docs/10.9/ref/crefsqlj34834.html