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.

Microsoft™ SQL Server

With Microsoft SQL Server, an object name takes the following form:

Object names are limited to 128 characters in SQL Server and cannot start with one of the following characters: @ (local variable) # (temp object).

To support double quotes as string delimiters in SQL Server, you can switch OFF the database option "Use quoted identifiers" in the database properties panel. But quoted table and column names are not supported when this option is OFF.


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.

With Microsoft SQL Server, use a "CS" case-sensitive collation at server and database level. See Case sensitivity for more details.

Check for single or double quoted table or column names in your source and remove them.

If cross-database queries are required (using the dbname:tabname Informix notation), consider to create views in the main database in SQL Server, to allow program to access the distant table from the same database connection:
CREATE VIEW myotherdb_customers AS SELECT * FROM myotherdb.dbo.customers