Database connection types in oracle

In Oracle, there are several types of database connections, each serving different purposes. Here are some common types of database connections in Oracle:

1.    Local Connection:

·  A local connection refers to connecting to an Oracle database on the same machine where the Oracle Database software is installed. This connection type uses the Oracle Database's local naming method.

CONNECT username/password@tns_entry

2.    Dedicated Server Connection:

·  In a dedicated server connection, each client process has its own dedicated server process on the Oracle database server. This provides a one-to-one relationship between the client and server processes.

CONNECT username/password@//hostname:port/service_name

3.    Shared Server (formerly Multi-Threaded Server) Connection:

·  Shared server connections allow multiple client processes to share a pool of server processes. This can be more resource-efficient than dedicated server connections, especially in environments with a large number of connections.

CONNECT username/password@//hostname:port/service_name

4.    SYSDBA and SYSOPER Connections:

·  SYSDBA (System Database Administrator) and SYSOPER (System Operator) connections are used for administrative tasks. These connections have powerful privileges to perform tasks such as database creation, startup, and shutdown.

CONNECT / AS SYSDBA

CONNECT / AS SYSOPER

5.    Proxy Connection:

·  Proxy connections allow one user to connect to the database on behalf of another user. This is often used for debugging or troubleshooting purposes.

ALTER USER proxy_user GRANT CONNECT THROUGH original_user; CONNECT proxy_user[original_user]/password@tns_entry

6.    Database Link Connection:

·  A database link allows a user to connect to a remote Oracle database and access objects in that database. It enables distributed database functionality.

CREATE DATABASE LINK link_name CONNECT TO remote_user IDENTIFIED BY password USING 'remote_tns_entry';

7.    OCI (Oracle Call Interface) Connection:

·  OCI is a low-level programming interface that enables applications to interact with Oracle databases. It provides a way to connect to Oracle databases using languages like C, C++, and others.

Example in C:

#include <oci.h>

8.    JDBC (Java Database Connectivity) Connection:

·  JDBC is a Java-based API that allows Java applications to interact with relational databases, including Oracle. It provides a standard interface for connecting to databases and executing SQL queries.

Example in Java:

import java.sql.Connection; import java.sql.DriverManager;

These are just some of the common connection types in Oracle. The choice of connection type depends on factors such as security requirements, resource utilization, and the specific needs of the application or task at hand.