Either an Open Client library application or an Embedded SQL application can be used to send SQL commands to Adaptive Server Enterprise.
Generally, Embedded SQL is a superset of Transact-SQL. An Embedded SQL application includes Embedded SQL commands intermixed with the application’s host language statements. The host language precompiler processes the Embedded SQL commands into calls to Client-Library routines and leaves the existing host-language statements as is. All version 10.0 or later precompilers use a runtime library composed solely of documented Client-Library and CS-Library calls.
In a sense, then, the precompiler transforms an Embedded SQL application into a Client-Library application.
An Open Client library application sends SQL commands through library routines, and does not require a precompiler.
Generally, an Embedded SQL application is easier to write and debug, but a library application can take fuller advantage of the flexibility and power of Open Client routines.