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Designing databasesThe 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 DatabaseThe 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.
Object-relational databases
Create and use extended data types in Informix®
Smart large objects
Use smart large objects

Use smart large objects

To store columns of a BLOB or CLOB data type, you must allocate an sbspace. An sbspace is a logical storage unit that stores BLOB and CLOB data in the most efficient way possible. You can write Informix® ESQL/C programs that allow users to fetch and store BLOB or CLOB data. Application programmers who want to access and manipulate smart large objects directly can consult the Informix ESQL/C Programmer's Manual.

In any SQL statement, interactive or programmed, a BLOB or CLOB column cannot be used in the following contexts:

In arithmetic or Boolean expressions
In a GROUP BY or ORDER BY clause
In a LIKE or MATCHES condition
In a UNIQUE test
For indexing, as part of a B-tree index
DataBlade® developers, however, can create indexes on CLOB columns.

In a SELECT statement entered interactively, a BLOB or CLOB column can:

Specify NULL values as a default when you create a table with the DEFAULT NULL clause
Disallow NULL values using the NOT NULL constraint when you create a table
Be tested with the IS [NOT] NULL predicate

From an ESQL/C program, you can use the ifx_lo_stat() function to determine the length of BLOB or CLOB data.

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