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Designing databases
The first step in creating a relational database is to construct a data model, which is a precise, complete definition of the data you want to store. After you prepare your data model, you must implement it as a database and tables. To implement your data model, you first select a data type for each column and then you create a database and tables and populate the tables with data. You can also implement fragmentation strategies and control access to your data.
Designing and Implementing a Database
The Informix® Database Design and Implementation Guide provides information to help you design, implement, and manage your Informix databases. It includes data models that illustrate different approaches to database design and shows you how to use structured query language (SQL) to implement and manage your databases.
Basics of database design and implementation
Plan a database
Use ANSI-compliant databases
Differences between ANSI-compliant and non-ANSI-compliant databases
DECIMAL data type

Designing databases
The first step in creating a relational database is to construct a data model, which is a precise, complete definition of the data you want to store. After you prepare your data model, you must implement it as a database and tables. To implement your data model, you first select a data type for each column and then you create a database and tables and populate the tables with data. You can also implement fragmentation strategies and control access to your data.
- Designing and Implementing a Database
  The Informix® Database Design and Implementation Guide provides information to help you design, implement, and manage your Informix databases. It includes data models that illustrate different approaches to database design and shows you how to use structured query language (SQL) to implement and manage your databases.

DECIMAL data type

If a database is not ANSI-compliant, a DECIMAL data type that you declare with a precision but no scale can store floating point values of the specified precision. If you specify neither precision nor scale, the default precision is 16.

In an ANSI-compliant database, all DECIMAL values are fixed-point and must be declared with an explicit precision. If you specify no scale for the DECIMAL data type, the scale = 0, and only integer values can be stored.