What is the difference between instance name and database name

I enter userid and password and unable to connect. I know I am repeating my wrong login steps knowingly as it will be connected using ABC only. Learn More. Sign in. United States English. Ask a question. Quick access. Search related threads. Remove From My Forums. The main difference between instance and database in SQL server is that an instance is a copy of the sqlservr. It consists of both GUI and command line.

SQL Server provides multiple advantages. It allows creating and managing databases and provides services such as analysis services and reporting services. What is Database — Definition, Functionality 3. An instance is a copy of the sqlserver. In other words, it is an installation of SQL Server. If the programmer installed SQL server n times, then n number of instances will be created. For example, if you sign in to an Oracle database, your login session is an instance.

If you log off or shut down your computer, your instance disappears, but the database and your data remain intact. An Oracle instance can access only one database at a time, while multiple instances can access an Oracle database. It's not the database; instead, it's the software used to create the database. Maintaining multiple instances might be useful when managing server resources. You can configure each instance for memory and CPU usage, which is something you can't do for individual databases within a SQL Server instance.

It may also be helpful to think of an instance in context with a database schema. The schema is the metadata that defines the database design and determines the methods for data organization. It includes a database's tables and their columns and any rules that govern the data. For instance, an employee table in a database might have columns for name, address, employee ID, and job descriptions. This arrangement is the structure, or schema, of the database.

While the database schema defines the organization of data, an instance of the database is a snapshot of the content at any given moment. This picture includes the data and its relationship to other data in the database at a particular time.

Actively scan device characteristics for identification. Can u provide a link or something to the documentation which clear this concept? I'll be thankful for your advise and any help for these issues will be highly appreciated. Regards, Saeed Dashti. May 24, - am UTC. Does Oracle support instances with the same SID on the same machine? YES - on unix. NO - on windows, the services are named after the sid. So, that is all I have to say on it, don't do it, it would not be a good idea.

Use DBCA and OUI database configuration assistant and oracle universal installer to manage the software, it will relink anything that is necessary for you. Dear Tom, Greetings, I had open up a tar and they have totally disagreed with what you said. Oracle doesn't support multiple databases running with same name on any platform.

Oracle uses these uinque names to derive names for oracle background process's in the system. It is not possible to have multiple background process's running with same process name in any system. I can provide you with the detail of TAR if required. May 25, - am UTC. I want for whatever reason two database instances up and running with that sid. So, I log into the ora9ir1 account.

A single software install can support multiple instances and databases -- each with their own SID hey, they could have the same db name if you wanted but that was be a really bad idea too -- the goal is to organize things, not to make things more confusing Why do you believe you want to install multiple times???

I mean what OS do u usually use? Regards, Kevin. May 26, - am UTC. A reader, August 05, - am UTC. August 05, - pm UTC. Tom, Your site is very helpful to me. Thank you for sparing your time to response for each our questions. And instance can start only ONE database at the time.

If it does, how can I make both databases 1stnewdb and 2ndnewdb be available at the same time?? Thanks for your response. Hi Tom, Just wondering what is the difference between parallel server and real application clusters? September 06, - pm UTC. The major difference - the 'biggest thing' -- is a technology refered to as cache fusion, the change in the way blocks are shared between the nodes.

In OPS, a "ping" of a block required a write to disk on node 1 and a read on node 2. In RAC, that "ping" is done by sending the block over an interconnect, a high speed private network for keeping the caches in step with eachother. See the RAC concepts guide, useful for getting an overview of "whats new".

Hi Tom, I have login into the remot database using my username and password. I don't have any data dictionary access. How can i know that at which database i had connected means name of the database and instance?

September 16, - pm UTC. September 17, - am UTC. A database is a set of files. An instance is a collection of processes and memory. A database may be mounted and opened by one or more instances RAC An instance may only ever mount and open a single database in its entire life, you have to kill the instance shutdown the instance and create a new instance to open another database.

Your answer is very helpful, however, it's even better if you give us the result of "ps -aef grep mon" at your server as an example to help us regconize how many instance since after excuting ps command I saw many listed but can't tell whether all of them are instances.

October 06, - pm UTC. How to findout all the processes associated with a particular instance? Reji, February 04, - am UTC. Tom: We are writing an application which will determine the cpu and memory utilization of each and every application running on a server. How can we get the same information about oracle apps, oracle instances on a server? Thanks Reji. May 16, - pm UTC. A reader, May 14, - pm UTC. Hi I am recieving "An attempt to re-link the Oracle software has failed!

My database is in AIX platform. Please give the solution for this. My database version is What should we do to remove this error? June 10, - am UTC. Local connection to a instance only SID needed? I believe the value will be retrieved from the registry itself. Where it would find in the registry, will be dependant on the oracle.

All rights reserved. July 29, - am UTC. August 01, - am UTC. Like what you say, if no environment variable set, registry will be look at for its default value. August 03, - pm UTC. I don't know what you mean here. August 06, - pm UTC. Enter user-name: scott Enter password A reader, August 08, - pm UTC. Hello Tom 1- If I change the dbname, I always have to open with resetlogs. Therefore data in redolog may be lost 2- Both dbid,dbname are stored in controlfile, datafile and redologs.

Are these correct? August 11, - pm UTC. May 09, - am UTC.