Perhaps the biggest advantage to accessing data through ODBC is the ability to access a wide range of data with just one interface. Since most popular Database Management Systems now offer ODBC drivers, with more appearing every day, Crystal Reports can use any type of data you have.
Because of the extreme flexibility built into ODBC, you can use the same report file with different ODBC data sources. For example, you might design a report using an Oracle data source, and later, if your company switches to Microsoft SQL Server, you can simply change the ODBC data source used by your report. The only requirement is that the new data source must have the same structure (tables and fields) that the original data source had (although table names can be different). See Changing the ODBC data source accessed by a report.
Experienced SQL (Structured Query Language) programmers also benefit from the ODBC standard. Since Crystal Reports uses SQL to communicate with ODBC, SQL programmers and Database Administrators can view and edit the SQL statements sent to ODBC, controlling exactly how data is retrieved from the data source.
Finally, by using SQL pass
Because of the many layers involved in passing data through ODBC from a database to an application, ODBC data sources often take more time to return data than natively accessed data sources. First, Crystal Reports must request some data. The request must be translated by the ODBC translation layer into a format that ODBC understands (an SQL statement). ODBC must determine where the requested data exists, and pass the request on to the ODBC data source. For more information, see DBMS translation (ODBC data source) layer. The data source must analyze the request and translate it again into a format that can be understood by the DBMS. This complex process not only takes time, but it can also fail at any of several possible levels.
In addition, ODBC data sources must be correctly configured and set up in the Odbc.ini and Odbcinst.ini files before they can be used. If you create a report on one system and try to open it on another system that does not have the same ODBC data source set up, Crystal Reports will not be able to connect to the data.
When working with ODBC, you should also be aware that the SQL language used by ODBC is based on the standards set for the SQL language by the American National Standards Institute (ANSI). Some SQL
The process by which Crystal Reports accesses data from an ODBC data source consists of five layers:
By using the Structured Query Language (SQL), all five layers can conveniently pass data from the database to your report.
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