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.
Question:- List out the tools for administering the database.
Answer:- Following are some of the products, tools, and utilities we use in achieving our goals as a Database Administrator: • Oracle Universal Installer (OUI): The Oracle Universal Installer installs the Oracle software and options. It can automatically launch the Database Configuration Assistant to install a database. • Database Configuration Assistant (DBCA): The Database Configuration Assistant creates a database from the templates that are supplied by Oracle, or we can create our own templates. In this case, it enables us to copy a preconfigured seed database, thus saving the time and effort of customizing and generating a database from scratch. • Database Upgrade Assistant: This tool guides us through the upgrading of our existing database to a new Oracle release. • Oracle Net Manager: This tool guides us through our Oracle network configuration. • Oracle Enterprise Manager: The primary tool for managing our database is Oracle Enterprise Manager, a web-based interface. Once we install the Oracle software, create or upgrade a database, and configure the network, we can use Oracle Enterprise Manager as the single interface for managing our database. In addition, Oracle Enterprise Manager also provides an interface for performance advisors and an interface for Oracle utilities such as SQL*Loader and Recovery Manager.
Question:- Differentiate between a cluster and a grid.
Answer:- Clustering is one technology used to create a grid infrastructure. Simple clusters have static resources for specific applications by specific owners. Grids, which can consist of multiple clusters, are dynamic resource pools shareable among many different applications and users. A grid does not assume that all servers in it are running the same set of applications. Applications can be scheduled and migrated across servers in the grid. Grids share resources from and among independent system owners. At the highest level, the idea of grid computing is computing as a utility. In other words, we need not care where our data resides or which computer processes our request. We should be able to request information or computation and have it delivered as per our requirement. This is analogous to the way the electric utilities work; without knowing where the generator is or how the electric grid is wired, we just ask for electricity and we get it. The goal is to make computing a utility, a commodity, and ubiquitous. Hence the name ‘Grid’. This perspective of utility computing is, of course, a ‘client-side’ view. From the ‘server-side’ (or behind the scenes), the grid is about resource allocation, information sharing, and high availability. Resource allocation ensures that all those, who request resources, are getting what they need and that those resources are not standing idle while requests go unserviced. Information sharing makes sure that the information, the users and applications need, is available as and when it is requested for. High availability features guarantee that all the data and computation are always available as a utility.
Question:- Explain the architecture of Oracle Grid.
Answer:- The Oracle Grid architecture pools large numbers of servers, storage, and networks into a flexible, on-demand computing resource for enterprise computing needs. The grid computing infrastructure continually analyzes the demand for resources and adjusts the supply accordingly. For example, we can run different applications on a grid of several linked database servers. When reports are due at the end of the month, the Database Administrator can automatically provision more servers to that application to handle the increased demand. Grid computing uses sophisticated workload management that makes it possible for applications to share resources across many servers. Data processing capacity can be added or removed on demand, and resources within a location can be dynamically provisioned. Web services can quickly integrate applications to create new business processes.
Question:- What are the tools you can use to start up an Oracle database?
Answer:- You can start up a database using three tools: 1. SQL *Plus: To startup an Oracle database instance, you can use the SQL *Plus startup command. 2. Oracle Enterprise Manager: It is a system management tool, you can startup the Oracle database with Oracle enterprise manager also. It provides an integrated solution for managing your heterogeneous environment. Even if the database is stopped you can still log in to OEM. It will present you with the Startup button by detecting the status of the down database. 3. Recovery Manager: RMAN is also known as the RMAN repository that is connected with the TARGET keyword which is also a database on which RMAN performs backup and recovery operations in the control file of the database.
Question:- What would you specify in the script while creating a database with SQL script?
Answer:- An SQL script can also be used to build a database. I will include the following in this script: • The database’s name • The SYS user’s password. • The Device user’s password. • At least three redo log classes are available online. In my view, each redo log group should have at least two members. • The database’s character set and national character set. • SYSTEM and SYSAUX tablespace locations and sizes. These tablespaces will be used to store device information. • As the database’s default tablespace, I will define a normal tablespace. • I’d specify a temporary tablespace to use as the database’s default temporary tablespace. • I’d build an undo tablespace.
Question:- Can you find out the indexes for a table in Oracle ?
Answer:- This is the basic syntax that is used to find out the indexes for a table in Oracle. SELECT owner, index_name, tablespace_name, status Set pages Break on table_name on index_name column table_name column index_name column column_name select table_name, index_name, column_name from dba_ind_columns where table_owner order by table_name, index_name column_position
Question:- What is SQL*plus? And what can be done with it?
Answer:- SQL* Plus is a component of Oracle Database. It is basically a command-line tool that allows you to submit SQL queries to the server interactively. • We can view the results by Running a SELECT query • With SQL*Plus we can startup and shutdown a Oracle database. • Submit PL/SQL blocks for execution to the Oracle server. • Execution of SQL*Plus script file can be done. • Create, modify, or drop database objects(eg., tables, indexes, and users) using DDL statements, as well as any other SQL statements that Oracle supports. • We can write the output to a file. • Execute stored procedures and functions in a database
Question:- Can you explain each digit in the Oracle database version?
Answer:- 1. This first digit indicates the major database version and it describes the nature of release. Oracle releases a new release every four years on average. For example: Oracle 9i (internet), Oracle 10g (grid), Oracle 11g (grid), Oracle 12c (cloud). 2. The second digit represents the software’s maintenance release number. Oracle releases the major update as maintenance release 1 and then follows up with a second maintenance release later in the software’s lifecycle. With maintenance releases, new features are introduced to database software. For example: Oracle 12c release 1; Oracle 12c release 2. 3. Fusion Middleware Number is the third digit. This will be 0 for database software. 4. This fourth digit is called Component-Specific Release Number And a component release level is identified by the fourth digit. Depending on component patch sets or temporary releases, different components can have different numbers in this role. Example: 12.1.0.1; 12.1.0.2; 12.2.1.1 5. A platform- specific release is identified by the fifth digit. This is usually a patch kit. this digit will be the same across all affected platforms when different platforms need the same patch package. Example: GA release (initial release-no patch): 12.2.0.1.0
Question:- What kind of information can be given while creating a sequence?
Answer:- Syntax for creating sequence: CREATE SEQUENCE schema_name. sequence_name [INCREMENT BY interval] [START WITH first_number] [MAXVALUE max_value | NOMAXVALUE] [MINVALUE min_value | NOMINVALUE] [CYCLE | NOCYCLE ] [CACHE cache_size | NOCACHE] [ORDER |NOORDER]; While creating a sequence, Use the CREATE SEQUENCE command and add a sequence_name and that should be unique. The next increment by is used to show how much the sequence will increment at each move. Then using START WITH, we start the sequence either in ascending or descending. And MAXVALUE, NOMAXVALUE are maximum limits. with max value we can provide the maximum sequence value whereas nomax value is fixed, 10^27 for ascending sequence or -1 for descending sequence. MINVALUE is to specify the minimum value of sequence. NOMINVALUE is fixed. For an ascending sequence it indicates a minimum value of 1 and -10^26 for a descending sequence. To allow the sequence to generate value after it reaches the limit, then use CYCLE which is the minimum value for a descending sequence and max value for an ascending sequence. NOCYCLE is a default and it will be used when the sequence reaches the limit and you want to stop generating the next value. And ORDER ensures that oracle generates sequence numbers in the order in which they are requested. if you don’t want Oracle to generate sequence numbers in the order of your requests, use NOORDER. This is a default setting.
Question:- Explain how the “Database Writer” process works?
Answer:- Multiple database context processes are possible. In the operating system, they are referred to as “DBWn.” This method is in charge of storing “dirty” buffers on disc. When a server process has to update a data block, it first reads it from disc into the buffer cache if it isn’t already there, and then updates the cache copy. So, a “dirty” block refers to a modified database block in the buffer cache.
Question:- What are the instance parameters that are used for configuring shared server architecture?
Answer:- • DISPATCHERS: In the shared server architecture, configures dispatcher processes. • MAX _DISPATCHERS: The maximum number of dispatcher processes that can run at the same time is defined. • SHARED_SERVERS: There will be a minimum of shared server processes on the server. This number of shared servers is determined during the initialization process. • MAX_SHARED_SERVERS: The maximum number of shared server processes that can run at the same time is determined by this parameter. • SHARED_SERVER SESSIONS: This is the only required parameter for using shared servers and it defines the maximum number of concurrent sessions that can be used for shared server connection. • CIRCUITS: The maximum number of virtual circuits that can exist in the system is determined by this parameter.
Question:- How to know when operations happened on a table?
Answer:- In the database, FLASHBACK_TRANSACTION_QUERY shows all information about flashback transaction queries. SELECT * FROM flashback_transaction_query WHERE TABLE_NAME AND table_owner and operation order by start_timestamp desc