Question:- Explain the advantages of using view?
Answer:- The advantages of using a view in the table are • It is a subset of the data in table • It store complex queries • It can simplify multiple tables into one • It occupies very little space • It presents the data from different perspectives
Question:- In Oracle terminology, what do you mean by tablespace?
Answer:- A tablespace is a logical storage unit that groups together similar logical structures. It is the logical structure that will organise all of the database’s objects.
Question:- How long does it take for the SYSTEM tablespace to be created?
Answer:- Every database in Oracle has a tablespace called SYSTEM, which is generated automatically when the database is created. It also includes a data dictionary table for the entire set of data.
Question:- What is the relationship between tablespace and datafiles?
Answer:- Each database has one or more tablespaces, each of which is divided into one or more data files.
Question:- How do we use the materialized view?
Answer:- Materialized views are items that contain condensed sets of data from base tables that have been summarised, clustered, or aggregated. They’re commonly used in data centres and decision-making systems.
Question:- What is the use of the SELECT statement?
Answer:- The SELECT statement is used to retrieve a collection of unique values from a database table based on the conditions defined in a SQL query.
Question:- How can you compare a part of the name rather than the entire name?
Answer:- To compare different parts, we use the LIKE operator, which functions as a database’s regex engine.
Question:- What is the keyword to get distinct records from a table?
Answer:- The user will use SELECT DISTINCT to select distinct values from a database table.
Question:- In order to get sorted records from a table, what is the keyword?
Answer:- The keyword ORDER BY is used to sort the data.. It returns the sorted results to your program.
Question:- In order to get total records from a table, what is the keyword?
Answer:- The COUNT keyword is used to find the total number of records in a table.
Question:- What is the definition of GROUP BY?
Answer:- The keyword GROUP BY is an aggregate function like SUM, MULTIPLE, and so on, and without it, the sum for each individual group value cannot be determined.
Question:- What are the methods to shutdown an Oracle database?
Answer:- Oracle has several modes for shutting down the database 1. Normal Mode: In normal mode the database is shut down by default. It can be used when no other clause is provided. the database waits for all currently linked users to detach from the database before shutting it down and no new connections are permitted once the statement is released. The command line is SHUTDOWN NORMAL 2. Transactional Mode: Transactional mode helps to shut down the database while allowing to complete the active transactions. In this process, no new connections are allowed and this mode waits for all transactions to finish before shutting down the database. Use this command line to shut down the database SHUTDOWN TRANSACTIONAL 3. Immediate Mode: When you know a power outage is coming up fast, then you can use immediate mode. All sessions will be disconnected, all running transactions will be rolled back, the database does not wait for existing database users to disconnect until proceeding and the database will be shut down. No instance recovery is needed during this next startup. Issue the command SHUTDOWN with an IMMEDIATE clause to shut down a database immediately. SHUTDOWN IMMEDIATE 4. Abort Mode: When you want to shut down the database immediately within seconds without any active transactions then you can use this abort method. Hereafter the statement has been released, no new connections or transactions are permitted to be initiated. The Oracle database automatically terminates all current client SQL statements and does not wait for existing database users to disconnect. Transactions that have not been committed will not roll back. All linked users are automatically disconnected by the database. Use the command SHUTDOWN with ABORT clause: SHUTDOWN ABORT
Question:- What are the benefits of ORDBMS?
Answer:- In ORDBMS, the objects can be stored as they are. The language of the DBMS can be integrated with an object-oriented programming language. The language may even be exactly the same as that used in the application, which does not force the programmer to have two representations of his objects.
Question:- What are the common Oracle DBA tasks?
Answer:- As an Oracle DBA, we have to carry out the following tasks: • Installing Oracle software • Creating Oracle databases • Performing upgrades of the database and software to new release levels • Starting up and shutting down the database • Managing the database’s storage structures • Managing users and security • Managing schema objects, such as tables, indexes, and views • Making database backups and performing recovery when necessary • Proactively monitoring the database’s health and taking preventive or corrective actions as required • Monitoring and tuning performance In a small-to-midsize database environment, a single DBA might be the sole person performing all these tasks. In large enterprise environments, the whole job is often divided among several DBAs titled as Database Security Administrator or Database Tuning Expert, each with his/her own area of specialties.
