Before designing a report, you first need to know what type of data you will be working with. The business and technology worlds use countless different names to refer to databases. Throughout this book, however, I will stick to the tc.rm database to refer to a generic source of data from which a report pulls information. Database always refers to whatever specific pool of data you pull from to generate a report. Seagate Crystal Reports supports reporting through three types of connections:
• Direct Connection, Databases, of which there are countless vendors, hold data either in files or tables, on your client workstation, or a large server somewhere on your network. SCR is able to connect to these databases through the use of DSNs with the Data Explorer.
• Crystal Dictionaries. Dictionaries, created by the Crystal Dictionarytool, allow people who know the database well to create .a “pair of glasses” for other people to use when accessing the database. This metaphorical pair of glasses makes the database look much simpler to users not as familiar with the setup and structure of the database. People writing reports use this dictionary layer to access the database and make their job simpler.
• Query. Queries return subsets of data from a database. The Crystal SQL Designer allows you to design SQL queries for your database, which collect the data you specify and hold it in a query file. This query file can then be used as the database for a report.