Welcome
Data warehousing
In addition to designing and implementing Informix® dimensional databases, you can use tools to create data warehouse applications and optimize your data warehouse queries.
Dimensional databases
The IBM® Informix® Data Warehouse Guide provides information to help you design, implement, and manage dimensional databases, and describes the tools that you can use to create data warehouses and optimize your data warehouse queries.
Design a dimensional data model
To build a dimensional database, you start by designing a dimensional data model for your business.
Building a dimensional data model
Establish referential relationships
For the database server to support the dimensional data model, you must define logical dependencies between the fact tables and their dimension tables.
Choose the measures for the fact table
Keys to join the fact table with the dimension tables
Each dimensional table needs to include a primary key that corresponds to a foreign key in the fact table. The fact table should have a primary (composite) key that is a combination of the foreign keys.

HCL Informix® V15.0.0 documentation
Welcome to the documentation for HCL Informix® 15.0.0 and related client tools and products.
Product overview
HCL Informix® is a fast and scalable database server that manages traditional relational, object-relational, and dimensional databases. Its small footprint and self-managing capabilities are suited to embedded data-management solutions.
Installing
These topics describe how to install HCL Informix® database servers, client products, and modules.
Administering
In addition to administering the database server, you can tune performance, replicate data, and archive data.
Migrating and upgrading
You can upgrade to the 15.0.0 release of HCL Informix® or migrate from other database servers to Informix. Upgrading is an in-place migration method that uses your existing hardware and operating system software. Some changes to the Informix database server can affect upgrading from a previous release.
Client APIs and tools
You can use the HCL Informix® implementation of client APIs to develop applications for Informix database servers.
Embedding Informix®
When you embed HCL Informix®, you can use enterprise-class high-availability and high performance with embeddability features such as easy programmability, a small disk and memory footprint, and silent deployment.
Extending Informix®
Beyond standard relational database objects, HCL Informix® can be extended to handle specialized data types, access methods, routines, and other objects. Informix includes many built-in extensions that are fully integrated in the database server. Informix also provides modules, which are packages of extended database objects for a particular purpose and that are installed separately from the database server. Alternatively, you can create your own user-defined objects for Informix.
Data warehousing
In addition to designing and implementing Informix® dimensional databases, you can use tools to create data warehouse applications and optimize your data warehouse queries.
- Dimensional databases
  The IBM® Informix® Data Warehouse Guide provides information to help you design, implement, and manage dimensional databases, and describes the tools that you can use to create data warehouses and optimize your data warehouse queries.
  - Dimensional databases
    A dimensional database is a relational database that uses a dimensional data model to organize data. This model uses fact tables and dimension tables in a star or snowflake schema.
  - Design a dimensional data model
    To build a dimensional database, you start by designing a dimensional data model for your business.
    - Concepts of dimensional data modeling
    - Building a dimensional data model
      - A business process
        A business process is an important operation in your organization that some legacy system supports. You collect data from this system to use in your dimensional database.
      - Summary of a business process
      - Determine the granularity of the fact table
        After you gather all the relevant information about the subject area, the next step in the design process is to determine the granularity of the fact table.
      - Identify the dimensions and hierarchies
        After you determine the granularity of the fact table, it is easy to identify the primary dimensions for the data model because each component that defines the granularity corresponds to a dimension.
      - Establish referential relationships
        For the database server to support the dimensional data model, you must define logical dependencies between the fact tables and their dimension tables.
        Choose the measures for the fact table
        Keys to join the fact table with the dimension tables
        Each dimensional table needs to include a primary key that corresponds to a foreign key in the fact table. The fact table should have a primary (composite) key that is a combination of the foreign keys.
        Resisting normalization
        Efforts to normalize a dimensional database can actually prohibit an efficient dimensional design.
        Choose the attributes for the dimension tables
      - Fragmentation: Storage distribution strategies
        The performance of data warehousing applications can typically benefit from distributed storage allocation designs for partitioning a database table into two or more fragments. Each fragment has the same schema as the table, and stores a subset of the rows in the table (rather than a subset of its columns).
    - Handle common dimensional data-modeling problems
  - Implement a dimensional database
    You will learn the SQL statements that you need to implement the dimensional data model
  - Performance tuning dimensional databases
    This section describes how to tune the performance of your queries and to understand data distribution statistics.
- Informix® Warehouse Accelerator
  The IBM® Informix® Warehouse Accelerator Administration Guide includes information about installing and configuring the accelerator server, creating data marts, accelerators, and accelerated query tables (AQTs).
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.
JSON compatibility
You can use the popular JSON-oriented query language created by MongoDB to interact with data stored in HCL Informix®.
Security
You can secure your Informix® database server and the data that is stored in your Informix databases. You can encrypt data, secure connections, control user privileges and access, and audit data security.
SQL programming
You can use the HCL Informix® implementation of the SQL language to develop applications for Informix database servers.
Troubleshooting HCL Informix®
Several troubleshooting techniques, tools, and resources are available for resolving problems that you encounter in your HCL Informix® database server environment.

Keys to join the fact table with the dimension tables

Each dimensional table needs to include a primary key that corresponds to a foreign key in the fact table. The fact table should have a primary (composite) key that is a combination of the foreign keys.

Assume that the following schema of shows both the logical and physical design of the database.

The "Sales Fact table" is in the center of the diagram. Lines illustrate the joins from the fact table to the four dimension tables: product, time, geography, customer. The reminder of the diagram is described in the surrounding text. — Figure 1. The Sales fact table references each dimension table

The database contains the following five tables:

Sales fact table
Product dimension table
Time dimension table
Customer dimension table
Geography dimension table

Each of the dimensional tables includes a primary key (product, time_code, customer, district_code), and the corresponding columns in the fact table are foreign keys. The fact table also has a primary (composite) key that is a combination of these four foreign keys. As a rule, each foreign key of the fact table must have its counterpart in a dimension table.

Additionally, any table in a dimensional database that has a composite key must be a fact table. This means that every table in a dimensional database that expresses a many-to-many relationship is a fact table. Therefore a dimension table can also be a fact table for a separate star schema. This type of dimensional database model is referred to as a snowflake schema.

Tip: The primary key should be a short numeric data type (INT, SMALLINT, SERIAL) or a short character string (as used for codes). Do not use long character strings as primary keys.