RDBMS are almost always designed as client/server systems:
- The server is the process that does the hard work
- Reads and writes the physical files containing the data.
- Checks that a user may login, and checks privileges.
- Handles inserts, updates, deletes.
- Performs the selects, applies all possible optimizations.
- Communicates with the clients: receives queries, returns results.
- The client is a process that issues the commands to do inserts,
updates, deletes, selects.
- The client uses the database through a connection to the
- It never accesses the data directly.
- The client may execute on the same machine, or connect via the
net from some other machine.
- The client may be a GUI, a command-line interface, or some
process doing calculations.
- Most RDBMS has a ready-made shell-like client allowing a user
to work interactively with a database using SQL commands.
- Programs can become clients by using APIs (Application
Programming Interfaces) in the code to access the data.
- Interfaces exist for C, C++, Perl, Python for most RDBMS systems.
© 2001 Per Kraulis
$Date: 2001/05/09 14:30:50 $