18 SQL DBA Interview Questions With Example Answers

This index reorders the physical order of the table and searches based on the basis of key values. Within the clause, each SELECT query must have the same amount of columns. In a table, a record represents a collection of connected data.

If your (next) job requires working with relational databases, there’s a good chance you’ll need to do that in SQL Server. For example, data modelers design and implement databases with the help of database administrators. To do that, data modelers will use SQL Server how to become a sql dba developer to create tables and their attributes, define relationships between the tables, define constraints, data types, and so on. The database must then be filled with data, which is a data engineer’s job. They use SQL Server to query, integrate, transform, and load data.

Understanding SQL Joins – All You Need To Know About SQL Joins

It is Allocated by Database Server at the Time of Performing DML operations on the Table by the User. You may refer to this article WHERE clause for more details on the LIKE operator. For more details, please read the SQL | Functions (Aggregate and Scalar Functions) article. These are then translated into a conceptual model using tools like ER diagrams.

• For more details, please read SQL
• For more details please refer to our Stored procedures in the SQL article.
• INSERT, UPDATE, and DELETE commands are allowed in the stored procedures but not in functions.
• For disaster recovery, I implement a combination of off-site storage and cloud-based solutions.
• We’ve arranged them here from the most simple to the most complex.
• Ask your candidates some of these 10 situational SQL Server DBA interview questions to learn how candidates respond to complex SQL Server tasks.
• If you’re new to writing code, SQL makes an excellent, beginner-friendly first language.

These fields are often used in join conditions or in WHERE clauses. MINUS will display the results of query1 and remove those that match any records from query2. But, UNION will combine the results from query1 with query2 and remove duplicate records.

What is MySQL? – An Introduction To Database Management Systems

Table variables are used in functions, stored procedures, and batches. It deletes all the rows from the table; you cannot  use it for deleting only some rows. Another difference is that TRUNCATE doesn’t record each row’s changes to the log, so it’s faster than DELETE. DELETE erases row by row, with each deletion recorded in the log.

• Look for more details in the article explaining CTEs in SQL Server.
• MINUS will display the results of query1 and remove those that match any records from query2.
• On SQL Server 2005, installing the SQL Server failover cluster is a single-step process whereas on SQL Server 2008 or above it is a multi-step process.
• For example, you can use input validation to prevent SQL injection attacks, and you can encrypt sensitive data to prevent unauthorized access and data leakage.
• Applicants must practice answering the most anticipated SQL Server DBA interview questions before attending the interviews.
• By asking you to identify common problems and offer solutions, they can get a better sense of how you would handle difficult situations.

T-SQL has huge importance since all the communications with an instance of an SQL server are done by sending Transact-SQL statements to the server. Stored Procedures are created to perform one or more DML operations on databases. It is nothing but a group of SQL statements that accepts some input in the form of parameters and performs some task and may or may not return a value. For more details please refer to our Stored procedures in the SQL article. Data integrity is defined as the data contained in the database being both correct and consistent. For this purpose, the data stored in the database must satisfy certain types of procedures (rules).

What are the different types of Replication and why are they used?

This is the answer that lets the interviewer know how suitable are you for the position to which you are being interviewed. Beware though that re-computing the query statistics causes queries to be recompiled. This may or may not negate all performance gains you might have achieved by calling update statistics.

An execution plan is a graphic or text visualisation of how the database’s optimiser will run a query. They are useful for helping a developer understand and analyse the performance of their query. A clustered index is a type of index that reorders how the records are stored on the disk. DROP is used to remove database objects from the database, such as tables or views. This SELECT query can select data from the same table, or another table, or a combination of tables using JOINs, just like a regular SELECT query. You start by writing an INSERT INTO statement, along with the columns you want, and then instead of the VALUES clause, you write a SELECT query.