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SQL programming
You can use the HCL Informix® implementation of the SQL language to develop applications for Informix database servers.
Guide to SQL: Tutorial
The Informix® Guide to SQL: Tutorial shows how to use basic and advanced structured query language (SQL) to access and manipulate the data in your databases. It discusses the data manipulation language (DML) statements as well as triggers and stored procedure language (SPL) routines, which DML statements often use.
Database concepts
Important database terms
The relational database model

SQL programming
You can use the HCL Informix® implementation of the SQL language to develop applications for Informix database servers.
- Guide to SQL: Syntax
- Guide to SQL: Reference
  The Informix® Guide to SQL: Reference contains the reference information for the system catalog tables, data types, and environment variables of the HCL Informix dialect of the SQL language, as implemented in HCL Informix. These topics also include information about the stores_demo, sales_demo, and superstore_demo databases that are included with HCL Informix.
- Guide to SQL: Tutorial
  The Informix® Guide to SQL: Tutorial shows how to use basic and advanced structured query language (SQL) to access and manipulate the data in your databases. It discusses the data manipulation language (DML) statements as well as triggers and stored procedure language (SPL) routines, which DML statements often use.

The relational database model

The databases you create with the Informix® database server are object-relational databases. In practical terms this means that all data is presented in the form of tables with rows and columns where the following simple corresponding relationships apply.

Relationship: Description
table = entity: A table represents all that the database knows about one subject or kind of thing.
column = attribute: A column represents one feature, characteristic, or fact that is true of the table subject.
row = instance: A row represents one individual instance of the table subject.

Some rules apply about how you choose entities and attributes, but they are important only when you are designing a new database. (For more information about database design, see the Informix® Database Design and Implementation Guide.) The data model in an existing database is already set. To use the database, you need to know only the names of the tables and columns and how they correspond to the real world.