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.


With PostgreSQL, a database object name takes the following form:

You can define a list of schemas to be searched when the database object is not qualified. The list of schemas to look in is specified with SET search_path TO schema-1,schema-2,... for an SQL session (it can also be defined at the database level and user definition level).

When creating a table without a schema prefix, the table is created in the "public" schema. This schema is listed in the search path by default.


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.
Use the following FGLPROFILE entry to define the schema search path for programs connecting to PostgreSQL:
dbi.database.stores.pgs.schema = "\"$user\",public,stock"

For more details see PostgreSQL specific FGLPROFILE parameters.