File Name: sql server dba scenario based interview questions and answers .zip
In this article, we will discuss a number of questions that you may be asked when applying to a junior SQL Server database administrator DBA position. Which permission should you grant him?
- SQL DBA Interview Questions & Answers
- SQL Server DBA Interview Questions
- SQL Server Junior Database Administrator Scenario-Related Interview Questions and Answers
- Sql Server Dba Interview Questions And Answers Pdf
SQL DBA Interview Questions & Answers
What are the different types of backups? Answer: The SQL server offers 4 types of backups to suit the need of the administrator. Complete backup :The complete back up is just zipping the content of the entire database in terms of the different tables and procedures etc. This back up can server as an independent entity that can be restored in different systems with just the base SQL server installed. Transaction log backup: This is the mechanism of backing up the transaction logs that have been maintained in the server.
This way the details of the database getting updated is obtained. This cannot be a stand-alone back up mechanism. But can save a lot of time if we already have the file system related to the DB backed up on the new deployment server. Differential backup: This is a subset of the complete backup, where only the modified datasets are backed up.
This can save the time when we are just trying to maintain a backup server to main server. File backup: This is the quickest way to take the backup of entire database.
Instead of taking in the data actually stored in DB, the files are backed up and the file system thus obtained when combined with the transaction logs of the original system will render the database that we are trying to back up. What are the different levels of isolation? Answer: The isolation represents the way of separating the database from the effects of network accesses, thereby maintaining the consistency.
The different levels of isolation are: read committed: This level of isolation uses the shared locks and the reads to the database give the constant and consistent values. This is the least effective isolation level. Values can change within a specific transaction of a SQL function.
What are the steps to take to improve performance of a poor performing query? Answer: Maximum use of indexes, stored procures should be done. Avoid excessive use of complicated joins and cursors. Avoid using conditional operators using columns of different tables. Make use of computed columns and rewriting the query. What is normalization? Explain different levels of normalization? Answer: Check out the article Q from Microsoft knowledge base and of course, there's much more information available in the net.
Most of the times, it will be okay if you can explain till third normal form. What is denormalization and when would you go for it? Answer: As the name indicates, denormalization is the reverse process of normalization. It's the controlled introduction of redundancy in to the database design. It helps improve the query performance as the number of joins could be reduced. How do you implement one-to-one, one-to-many and many-to-many relationships while designing tables?
Answer : One-to-One relationship can be implemented as a single table and rarely as two tables with primary and foreign key relationships. One-to-Many relationships are implemented by splitting the data into two tables with primary key and foreign key relationships. Many-to-Many relationships are implemented using a junction table with the keys from both the tables forming the composite primary key of the junction table.
It will be a good idea to read up a database designing fundamentals text book. What's the difference between a primary key and a unique key? Answer: Both primary key and unique enforce uniqueness of the column on which they are defined. But by default primary key creates a clustered index on the column, where are unique creates a nonclustered index by default. What are user defined datatypes and when you should go for them?
Answer : User defined datatypes let you extend the base SQL Server datatypes by providing a descriptive name, and format to the database. In all these tables it should be varchar 8. What is bit datatype and what's the information that can be stored inside a bit column? Answer : Bit datatype is used to store boolean information like 1 or 0 true or false.
Untill SQL Server 6. But from SQL Server 7. Define candidate key, alternate key, composite key. Answer: A candidate key is one that can identify each row of a table uniquely. Generally a candidate key becomes the primary key of the table. If the table has more than one candidate key, one of them will become the primary key, and the rest are called alternate keys. A key formed by combining at least two or more columns is called composite key. What are defaults? Is there a column to which a default can't be bound?
Answer: A default is a value that will be used by a column, if no value is supplied to that column while inserting data. What is a transaction and what are ACID properties? Answer : A transaction is a logical unit of work in which, all the steps must be performed or none.
These are the properties of a transaction. Explain different isolation levels Answer: An isolation level determines the degree of isolation of data between concurrent transactions. Here are the other isolation levels in the ascending order of isolation : Read Uncommitted, Read Committed, Repeatable Read, Serializable. See SQL Server books online for an explanation of the isolation levels. What type of Index will get created after executing the above statement?
Answer: Non-clustered index. Important thing to note: By default a clustered index gets created on the primary key, unless specified otherwise. What's the maximum size of a row? Answer: bytes. Don't be surprised with questions like 'what is the maximum number of columns per table'. What is lock escalation? Answer: Lock escalation is the process of converting a lot of low level locks like row locks, page locks into higher level locks like table locks. Every lock is a memory structure too many locks would mean, more memory being occupied by locks.
To prevent this from happening, SQL Server escalates the many fine-grain locks to fewer coarse-grain locks. Lock escalation threshold was definable in SQL Server 6. What changed between the previous version of SQL Server and the current version? What are constraints? Explain different types of constraints. Answer: Constraints enable the RDBMS enforce the integrity of the database automatically, without needing you to create triggers, rule or defaults. Whar is an index? What are the types of indexes?
How many clustered indexes can be created on a table? I create a separate index on each column of a table. Answer: Indexes are of two types. Clustered indexes and non-clustered indexes. When you craete a clustered index on a table, all the rows in the table are stored in the order of the clustered index key. So, there can be only one clustered index per table.
Non-clustered indexes have their own storage separate from the table data storage. Non-clustered indexes are stored as B-tree structures so do clustered indexes , with the leaf level nodes having the index key and it's row locater. The row located could be the RID or the Clustered index key, depending up on the absence or presence of clustered index on the table. If you create an index on each column of a table, it improves the query performance, as the query optimizer can choose from all the existing indexes to come up with an efficient execution plan.
Another disadvantage is that, indexes need disk space, the more indexes you have, more disk space is used. Database administration Q. There are six RAID levels 0 through 5 offering different levels of performance, fault tolerance. What are the steps you will take to improve performance of a poor performing query?
Answer: This is a very open ended question and there could be a lot of reasons behind the poor performance of a query.
But some general issues that you could talk about would be: No indexes, table scans, missing or out of date statistics, blocking, excess recompilations of stored procedures, procedures and triggers without SET NOCOUNT ON, poorly written query with unnecessarily complicated joins, too much normalization, excess usage of cursors and temporary tables.
What are the steps you will take, if you are tasked with securing an SQL Server? Answer: Again this is another open ended question. Here are some things you could talk about: Preferring NT authentication, using server, databse and application roles to control access to the data, securing the physical database files using NTFS permissions, using an unguessable SA password, restricting physical access to the SQL Server, renaming the Administrator account on the SQL Server computer, disabling the Guest account, enabling auditing, using multiprotocol encryption, setting up SSL, setting up firewalls, isolating SQL Server from the web server etc.
What is a deadlock and what is a live lock? How will you go about resolving deadlocks? Answer: Deadlock is a situation when two processes, each having a lock on one piece of data, attempt to acquire a lock on the other's piece.
SQL Server detects deadlocks and terminates one user's process.
SQL Server DBA Interview Questions
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Are you prepared in attending an interview? Are you worried for job interview preparation? Then do not worry, you are at a right place. Below are the list of frequently asked SQL DBA interview questions and answers which can make you feel comfortable to face the interviews:. Question 1.
You are at accurate place. SVR Technologies give SQL Server training online at your registered time, you can choose classes where, when, and how it accommodates you the best. Here is the top 50 objective standard model SQL Server Dba Interview questions and their answers are provided just underneath to them. We have taken complete care to provide accurate answers to all the questions. What is BCP?
SQL Server Junior Database Administrator Scenario-Related Interview Questions and Answers
Explore Now! These questions and answers are suitable for both freshers and experienced professionals at any level. The source data will be copied to destination through replication agents jobs. Object level technology. The source data will be copied to destination via Transaction Log backup jobs.
Download PDF 1. What are the two authentication modes in SQL Server?
Sql Server Dba Interview Questions And Answers Pdf
Ans: Yes! Adding CPUs can occur physically by adding new hardware, logically by online hardware partitioning, or virtually through a virtualization layer. Requires hardware that supports hot-add CPU. How can we check whether the port number is connecting or not on a Server?
There are a lot of opportunities from many reputed companies in the world. What purpose does the Model Database Server? The model database , as its name implies, serves as the model or template for all databases created on the same instance.
What are the different types of backups? Answer: The SQL server offers 4 types of backups to suit the need of the administrator. Complete backup :The complete back up is just zipping the content of the entire database in terms of the different tables and procedures etc. This back up can server as an independent entity that can be restored in different systems with just the base SQL server installed. Transaction log backup: This is the mechanism of backing up the transaction logs that have been maintained in the server. This way the details of the database getting updated is obtained.
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