Top Answers to Oracle DBA Interview Questions
|Main storage structures||Logical and Physical|
|ACID Compliance||Fully compliant|
|Data stored as||Data blocks, extents, segments and table spaces|
Oracle is a company. Oracle is also a database server, which manages data in a very structured way. It allows users to store and retrieve related data in a multi user environment so that many users can concurrently access the same data. All this is accomplished while delivering high performance. A database server also prevents unauthorized access and provides efficient solutions for failure recovery. A standby database is a database replica created by taking a backup of a primary database.
Oracle provides software to create and manage the Oracle database. The database consists of physical and logical structures in which system, user, and control information is stored. The software that manages the database is called the Oracle database server. Collectively, the software that runs oracle and the physical database are called the Oracle database system. A database buffer cache stores the data in memory for quicker access. The redo logs track and store all the changes made to the database. A Data Guard ensures data protection and high availability of data and control file records the physical structure of the database. Click on the above link to read more and to become a Oracle DBA.
Learn more about Oracle DBA in Oracle DBA Tutorial.
DBA has the authority to create new users, remove existing users or modify any of the environment variables or privileges assigned to other users.
- Manage database storage
- Administer users and security
- Manage schema objects
- Monitor and manage database performance
- Perform backup and recovery
- Schedule and automate jobs
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The objects as such can be stored in the database. 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.
An index is an optional structure associated with a table to have direct access to rows, which can be created to increase the performance of data retrieval. Index can be created on one or more columns of a table.
As an Oracle DBA, you can expect to be involved in 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 action as required
- Monitoring and tuning performanceIn a small to midsize database environment, you might be the sole person performing these tasks. In large enterprise environments, the job is often divided among several DBAs, each with their own area of specialty, such as the database security administrator or database tuning expert.
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The following are some of the products, tools, and utilities you can use in achieving your goals as a database administrator.
-Oracle Universal Installer (OUI)
The Oracle Universal Installer installs your 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 templates that are Oracle supplied, or you can create your own. It enables you 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 you through the upgrade of your existing database to a new Oracle release.
-Oracle Net Manager
This tool guides you through your Oracle Net network configuration.
-Oracle Enterprise Manager
The primary tool for managing your database is Oracle Enterprise Manager, a web-based interface. After you have installed the Oracle software, created or upgraded a database, and configured the network, you can use Oracle Enterprise Manager as the single interface for managing your 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.
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 the grid 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, you should not care where your data resides, or what computer processes your request. You should be able to request information or computation and have it delivered – as much as you want, and whenever you want. This is analogous to the way electric utilities work, in that you don’t know where the generator is, or how the electric grid is wired, you just ask for electricity, and you get it. The goal is to make computing a utility, a commodity, and ubiquitous. Hence the name ‘The Grid’. This view 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 that need or request resources are getting what they need, that resources are not standing idle while requests are going unserviced. Information sharing makes sure that the information users and applications need is available where and when it is needed. High availability features guarantee all the data and computation is always there, just like a utility company always provides electric power.
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 demand for resources and adjusts supply accordingly.
For example, you could run different applications on a grid of several linked database servers. When reports are due at the end of the month, the database administrator could 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.