Name resolution of SQL objects


Informix uses the following form to identify an SQL object:

The ANSI convention is to use double quotes for identifier delimiters (For example: "customer"."cust_name").

Informix database object names are not case-sensitive in non-ANSI databases. When using double-quoted identifiers, Informix becomes case sensitive.

With non-ANSI Informix databases, you do not have to give a schema name before the tables when executing an SQL statement:
SELECT ... FROM customer WHERE ...
In Informix ANSI compliant databases:
  • The table name must include "owner", unless the connected user is the owner of the database object.
  • The database server shifts the owner name to uppercase letters before the statement executes, unless the owner name is enclosed in double quotes.


SQLite database object names are case-insensitive. Using double quotes to surround table names in possible. However, the letter case is kept even without double quotes:
sqlite> CREATE TABLE tab1 ( pk INT );
sqlite> CREATE TABLE "TAB2" ( pk INT );
sqlite> CREATE TABLE Tab3 ( pk INT );
sqlite> .tables
TAB2  Tab3  tab1
sqlite> .schema "TAB3" 

In an SQLite, if a prefix is specified as part of an object reference, it must be either "main", or "temp" or the schema-name of an attached database. There is no such concept as user schema in SQLite.


To write portable SQL, regarding database object names:
  1. Use simple database object names (without any owner/schema prefix)
  2. Do not use double quotes to surround database object identifiers.
  3. If needed, define public synonyms to reference database objects in others databases/schema.
  4. Specify database object identifiers in lowercase.
See also Naming database objects.