mysql vs sql server vs oracle vs db2 command

#Mysql vs sql server vs oracle vs db2 command software#

Oracle System Properties Comparison IBM Db2 vs. So Oracle deletes the objects in schema and then it drops the user automatically, Objects referred to these schema objects from other schema like views and private synonyms goes to invalid state.DBMS > IBM Db2 vs. If we try to drop a user containing objects in his schema we must specify CASCADE word because Oracle does not allow you to delete a user containing objects. here the restrict word forces you to specify that schema with out objects. We can drop the schema by using the DROP SCHEMA RESTRICT statement, but it can not delete schema contained objects, so to drop the schema, it must be empty. We can create schema by using the CREATE SCHEMA statement, but Oracle automatically creates a user for that schema. It contains all objects created by the user associated to that schema.For Example if i created a user with name santhosh then oracle creates a schema called santhosh, Oracle stores all objects created by user santhosh in the santhosh schema. It's created automatically by Oracle when user created. The Schema Also Logical Structure to process the data in Database(Memory Component). SchemaĪctually Oracle Database contain logical and physical structure to process the data. We can create user by using CREATE USER IDENTIFIED BY. User is a account to connect database(Server). The both words, user and schema, are interchangeable, that's why most people get confused on these words.

#Mysql vs sql server vs oracle vs db2 command software#

Its a physical Memory Component Connected to a Computer Installed with DBMS Software to manipulate the data in that Memory component,the computer installed with dbms software is called Server or Database Server.The both Server(Computer) and Database(memory component) are different but Most of times refered as Same based on situation. The Data base is a collection of data,where actually data stored. But using dbca (database creation assistant) is easier to get started.

You can create a database with the create database statement, once you've installed the Oracle software stack. You should look at the Oracle Database Architecture documentation in the Concepts Guide (actually, that whole page is worth a read - there's a section about users and schemas higher up in that page) to get an introduction to what a database is, and what a database instance is - two important concepts. The database is the thing that contains all the users you've created, and their data (and a bunch of predefined system users, tables, views, etc. Once the user is created, an administrator can grant privileges to the user, which will enable it to create tables, execute select queries, insert, and everything else. This also 'creates' the schema (initially empty) - you cannot create a schema as such, it is tied to the user. You create users with the create user statement. See this post on Stack Overflow: difference between a User and a Schema in Oracle? for more details and extra links. You can consider that a user is the account you use to connect to a database, and a schema is the set of objects (tables, views, etc.) that belong to that account.

In Oracle, users and schemas are essentially the same thing.