Databases Reference
In-Depth Information
Centralized model
Database deployment model characterized by a single database
server in a central location and accessed by local and remote users.
Change replication
Configuration where changed rows in a source table are written
to the destination, overwriting or inserting data as appropriate.
Check constraint
Constraint placed on table column to limit data values to a set range,
part of a specified list, or matching a format pattern.
Checkpoint
Transaction log entry that identifies the active portion of the log and forces
the database server to write dirty pages to the hard disk.
Clause
See keyword.
Clustered index
Index whose order is used to physically sort table data.
Command operators
Operator symbols and keywords used to run arithmetic, com-
parison, and logical operations.
Command syntax
The format used when specifying and executing a command,
including any keywords, and command parameters.
Commit
The process of successfully completing a transaction and finalizing its changes.
Commit phase
Final phase of a two-phase commit process in which transactions are
committed on distributed servers.
Common gateway interface (CGI)
A standard way for passing requests and data
between a Web server and an application.
Conceptual design
Database design process that includes data collection and identi-
fying data requirements.
Concurrency
Relating to supporting multiple users who need concurrent access,
access to the same data at the same time
Concurrency control
Database control over data access as a way to prevent errors
that can occur when multiple users try to modify the same data at the same time.
Concurrent transactions
Two or more transactions being processed at the same time.
Connection
A communication path.
Connection path
Physical communication path through which data travels.
Constraint
Limit or control placed on tables and table columns.
Consumer audience
Data consumers — the people or applications who need access
to data and who use data in some manner.
Control statement
A statement used to make a decision or otherwise control batch
execution.
Control-of-flow statement
See control statement.
Core business
A business' or organization's primary activity. The organization's justi-
fication for existence.
Correlated subquery
A query in which the inner query depends on values passed to
it from the outer query.
