If you are preparing for your interviews and you want to gain more knowledge on Oracle Database, then we are here to provide you the finest collections of questions that are frequently asked in interviews. Give a look at the questions listed in this article and get enhanced your knowledge.
Oracle is a database company that stores the data. Oracle stores the data in a very definite way so that client can regain it in a multi-user condition. It is very efficient for the client to access the same data by a few users. It is done in very high performance. Not only this, database prevents the unauthorized access that provides the security to the clients. Moreover, it provides solutions for failure restoration. There is a need for copying that is created by the backup of the primary database which is known as a standby database.
Oracle has the main theme of storing, creating and managing the database. For this, it has software i.e. Oracle Software which has the system of the physical and logical structure that contains the information of the user, control and much more. Oracle database server is the software that maintains the database. In a simple way, Oracle database system maintains and manages the Oracle and its physical database. Oracle solve its every quibble and try to keep it better. Like fast accessing in the database is possible now because of the functions like data buffer cache.
Moreover, it provides redo logs that take care of any change made in the database. More functions like Data Guard are present to protect the data and provide full security to the database. It also watches over the availability of data and also checks the file record. Data Guard also looks after the physical structure of the database.
DBA stands for the Database administrator. DBA has the proper rights that can add or remove new users. It can also modify the conditions or opportunities of the user.
Some of its roles in the database are: -
The important tasks of the Common Oracle DBA are mentioned below.
Here is the list of the tools that help the worker in administering the database.
-Oracle Universal Installer (OUI)
The Oracle Universal Installer is great to install for the Oracle software and many other options. It installs the database as it launched the database configuration Assistant all by itself.
-Database Configuration Assistant (DBCA)
It is significant to build a database from the database. It can be supplied by the Oracle or you can create it by self. It saves a lot of your precious time and effort managing and creating a database from scratch by replication of preconfigured seed database.
-Database Upgrade Assistant
It is important to keep your database up-to-date. It looks after the update of your present database.
-Oracle Net Manager
It guides you regarding the network of Oracle.
-Oracle Enterprise Manager
It is a very important tool of the Oracle as it manages and maintains the database. It is a web-based linkage. You are able to use Oracle Enterprise Manager as a single entity to maintain your database after a lot of hard work in creating or upgrading the database, design of the Oracle network etc. It is also valuable for the performance advisor as it provides an interface. Moreover, it also provides an interface like SQL* Loader for the Oracle services.
To depreciate the redundancy and necessity, the tables and the fields of a correlated database are organized. This process is known as Normalization
It helps to conserve the space for storage and look after the regularity of the data There are six various normal forms which are given below.
First Normal Form -
It is a level of database normalization where only atomic values are present in the fundamental domains.
Second Normal Form -
It is a level of database normalization where it is in first normal form and each non-key trait is completely functionally reliant on the primary key.
Third Normal Form -
It is a level of database normalization where it is in 2nd normal form and each non-key trait is non-transitionally reliant on the primary key.
Boyce Codd Normal Form -
It is a level of database normalization where each determinant is a candidate key.
Fourth Normal Form -
It is a level of database normalization where no non-trivial multivalent dependencies other than any candidate key is present
Fifth Normal Form -
It also referred to the project-join normal form. It is a level of database normalization which is created to lessen redundancy.
A database is the collection of three basic physical structure and these structures are data files, redo log files and control files which are stored in a disk whereas instance comprises an Oracle background process such as System MOnitor (SMON), Process MOnitor (PMON), Database writer (DBWR), Log WRiter (LGWR) and memory structure such as System Global Area (SGA), Program Global Area (PGA). These Oracle background Processes share a common memory area while running on a computer.
Another important difference between the database and an instance is that an instance is able to install and open only a single database whereas a database can be installed or opened by more than instance with the help of Real Application Cluster (RAC).
- SGA stands for System Global Area which is helpful to conserve the shared information all over the database users. It comprises of Data Dictionary cache, Library cache, Database Buffer Cache, Shared Pool, Redo log Buffer cache.
Oracle Grid Architecture is the factory of a great number of servers, storage, networks, computing resource at an instance for enterprise computing. It looks after the demands of resources and supply. Grid computing uses advanced technology that helps the users to share the resources over multiple servers. On the demand, it is possible to add or remove the data processing capacity. Resources are supplied in a location vigorously. Different web services can also combine to build a fresh business.
You can also perform SQL> show parameter control_files form SQL. This query gives you the information such as name, the location of the file in the disk.
You can make changes in the PFILE with the help of vi editor and control_files provide you with the information regarding the location and the name of the control files.
Following is the list of the advantage of using RMAN.
|SGA (System Global Area)||PGA (Program or Process Global Area)|
|It is a memory area assigned at the time of an instance start up.||It is a memory area that conserve the information regarding the user session.|
|It is distributed as 40% of RAM size.||It is distributed only 10% of RAM size.|
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