JDBC or Java Database Connectivity is a specification from Sun microsystems that provides a standard abstraction (that is API or Protocol) for java applications to communicate with various databases. JDBC along with the database driver is capable of accessing databases and spreadsheets.
The classes and interfaces of
JDBC allows application to send request made by users to the specified database.
Interacting with a database requires efficient
database connectivity which can be achieved by using the ODBC(Open
database connectivity) driver. This driver is used with JDBC to interact or
communicate with various kinds of databases such as Oracle, MS Access, Mysql
and SQL server database. JDBC provides the same
capabilities as ODBC, allowing Java programs to contain database-independent
code.
The JDBC library includes APIs for each of the tasks
mentioned below that are commonly associated with database usage.
- Making a connection to a database.
- Creating SQL or MySQL statements.
- Executing SQL or MySQL queries in the database.
- Viewing & Modifying the resulting records.
JDBC
Architecture
The JDBC API supports both two-tier and three-tier processing
models for database access but in general, JDBC Architecture consists of two
layers −
- JDBC API − This provides the application-to-JDBC Manager connection.
- JDBC Driver
API − This supports the JDBC
Manager-to-Driver Connection.
The JDBC API uses a driver manager and
database-specific drivers to provide transparent connectivity to heterogeneous
databases.
The JDBC driver manager ensures that the correct
driver is used to access each data source. The driver manager is capable of
supporting multiple concurrent drivers connected to multiple heterogeneous
databases.
Following is the architectural diagram, which shows
the location of the driver manager with respect to the JDBC drivers and the
Java application −
Common JDBC Components
The JDBC API provides the following interfaces and
classes −
- DriverManager − This class manages a list of database drivers. Matches
connection requests from the java application with the proper database
driver using communication sub protocol. The first driver that recognizes
a certain subprotocol under JDBC will be used to establish a database
Connection.
- Driver − This interface handles the communications with the database
server. You will interact directly with Driver objects very rarely.
Instead, you use DriverManager objects, which manages objects of this
type. It also abstracts the details associated with working with Driver
objects.
- Connection − This interface with all methods for contacting a database.
The connection object represents communication context, i.e., all
communication with database is through connection object only.
- Statement − You use objects created from this interface to submit the
SQL statements to the database. Some derived interfaces accept parameters
in addition to executing stored procedures.
- ResultSet − These objects hold data retrieved from a database after you
execute an SQL query using Statement objects. It acts as an iterator to
allow you to move through its data.
- SQLException − This class handles any errors that occur in a database
application.
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