Types of databases

You can connect to different types of databases, depending on what drivers you have installed with the Borland Database Engine (BDE) or ActiveX Data Objects (ADO).
These drivers may connect your application to local databases such as Paradox, Access, and dBASE or remote database servers like Microsoft SQL Server, Oracle, and Informix. Similarly, the InterBase Express components can access either a local or remote version of InterBase.

NB: Different versions of C++Builder come with the components that use these drivers (BDE or ADO), or with the InterBase Express components.

Choosing what type of database to use depends on several factors. Your data may already be stored in an existing database. If you are creating the tables of information your application uses, you may want to consider the following questions.

How much data will the tables hold?
How many users will be sharing these tables?
What type of performance (speed) do you require from the database?

Local databases
Local databases reside on your local drive or on a local area network. They have proprietary APIs for accessing the data. Often, they are dedicated to a single system. When they are shared by several users, they use file-based locking mechanisms. Because of this, they are sometimes called file-based databases.
Local databases can be faster than remote database servers because they often reside on the same system as the database application.
Because they are file-based, local databases are more limited than remote database servers in the amount of data they can store. Therefore, in deciding whether to use a local database, you must consider how much data the tables are expected to hold.

Applications that use local databases are called single-tiered applications because the application and the database share a single file system.
Examples of local databases include Paradox, dBASE, FoxPro, and Access.

Remote database servers
Remote database servers usually reside on a remote machine. They use Structured Query Language (SQL) to enable clients to access the data. Because of this, they are sometimes called SQL servers. (Another name is Remote Database Management system, or RDBMS.) In addition to the common commands that make up SQL, most remote database servers support a unique “dialect” of SQL.
Remote database servers are designed for access by several users at the same time. Instead of a file-based locking system such as those employed by local databases, they provide more sophisticated multi-user support, based on transactions.

Remote database servers hold more data than local databases. Sometimes, the data from a remote database server does not even reside on a single machine, but is distributed over several servers.
Applications that use remote database servers are called two-tiered applications or multi-tiered applications because the application and the database operate on independent systems (or tiers).
Examples of SQL servers include InterBase, Oracle, Sybase, Informix, Microsoft SQL server, and DB2.

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