User`s guide

Understanding Databases
23.1 Databases overview
Though there are hundreds of Database Management Systems (DBMS) available, Crystal Reports
eliminates many of the differences once it connects to the actual database files. The process of working
with database files, tables, fields, and records is much the same, regardless of the actual type of data
being accessed.
This section discusses several concepts and tasks common to working with database files. Using
database aliases, locating moved or renamed database files, working with indexed tables, and linking
tables are subjects common to anyone who designs reports in Crystal Reports. Using SQL and SQL
databases, is especially important for anyone who accesses data in SQL databases and other database
formats that are accessed through ODBC.
23.1.1 Relational database basics
The most popular architecture for database files used in the corporate world is based on the relational
model. Applications that allow you to create databases with the relational model are, therefore, often
referred to as Relational Database Management Systems (RDBMS).
In a relational database, data is organized in a system of rows and columns. The rows are called records,
and the columns are called fields. Each record contains a collection of related data, all information
relating to a specific customer, for example. Each field refers to a common type of data that exists in
all records, the names of the customers, for example. Records and fields are stored in a database table.
The following diagram illustrates the basic relational database model:
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Understanding Databases