Content
Select unique records from a table by using DISTINCT keyword. User defined functions are the functions written to use that logic whenever required. It is not necessary to write the same logic several times. Instead, function can be called or executed whenever needed. Data Integrity defines the accuracy and consistency of data stored in a database. It can also define integrity constraints to enforce business rules on the data when it is entered into the application or database. Constraint can be used to specify the limit on the data type of table.
It’s a good practice to return the required column instead of all the columns of a table. They improve the efficiency of the database engine in detecting lock conflicts at a higher level of granularity.
Q53. What is the difference between clustered and non-clustered index in SQL?
It also reduces network traffic and provides better security to the data. You can select unique records from a table by using the DISTINCT keyword. For example – UCASE(), NOW() are calculated with respect to string. The DISTINCT clause in SQL is used to eliminate duplicates from a SELECT statement’s result set. Getting access to secret data in order to change a SQL query to acquire the desired results. Example- In the Student table, Stu_ID is the primary key.
It is the nested query which is linked to the outer side query. For instance, we can say that we need to search out all the workers in WHO they do not enter time for the whole week. Find the SQL Server operating system information such as the OS version, processor number, physical memory, etc. There is one requirement though, the answers should not use T-SQL, such as in this way, invoke-sqlcmd -query “t-sql-code”. PowerShell is rich and deep in content itself, and it is almost impossible to come up with a comprehensive question list to check a candidate’s knowledge on every aspect of PS. But in the context of DBA work, we may come up with some good questions to test a DBA’s PowerShell knowledge. Here, we are copying student table to another table with the same structure with no rows copied.
What is recursive stored procedure?
UNION attacks are designed to steal data from several database tables. Clustered index is used for easy retrieval of data from the database and its faster whereas reading from non clustered index is relatively slower. Data Integrity defines the accuracy as well as the consistency of the data stored in a database. It also defines integrity constraints to enforce business rules on the data when it is entered into an application or a database.
- The international developer community has constantly backed it.
- According to ANSI, SQL is used for maintaining RDBMS and for performing different operations of data manipulation on different types of data by using the features of SQL.
- This means, it returns all the rows from the left hand side table and all the rows from the right hand side table.
- The file names start with the table name and end with an extension that indicates the file type.
- A database is an organized collection of structured data that can be stored, easily accessed, managed, and retrieved digitally from a remote or local computer system.
The file names start with the table name and end with an extension that indicates the file type. The table definition is stored in a.frm file, however this file is not part of the MyISAM engine; instead, it is part of the server. If you lose your index file, you may always restore it by recreating indexes. Automatic seeding is a feature launched in SQL Server 2016 to initialize the secondary replica. Earlier we have only one option to initialize secondary replica that is using backup, copy and restore database operation. We use this feature while creating the always on availability group. It is basically a set of SQL statements that allow input parameters, perform processing, and return results only.
Q26. What are UNION, MINUS and INTERSECT commands?
This tells SQL Server how much free space to leave in the index pages when re-indexing. The performance benefit here is fewer page splits because there is room for growth built into the index. SQL Agent is the job scheduling mechanism in SQL Server. Jobs can be scheduled how to become a sql server dba to run at a set time or when a specific event occurs. SQL Agent is most often used to schedule administrative jobs such as backups. Traces can be filtered to narrow down the transactions that are captured and reducing the overhead incurred for the trace.
First of all, set the optimizer to scan all the entries from the index instead of the table. Dynamic Sampling – Enables the server to enhance performance.
SQL Interview Questions and Answers for 2022
SQL server does not allow you to truncate the log now otherwise whole purpose of a DB is defeated. If you do not need log then have the recovery model simple instead of full.
