HCLTech SQL Developer Interview Questions and Answers

SQL commands are instructions used to interact with a database to perform tasks such as querying, updating, and managing data.

• SQL commands are used to interact with databases to perform tasks like querying data, updating data, and managing database structures.

• Common SQL commands include SELECT, INSERT, UPDATE, DELETE, CREATE, and DROP.

• Examples: SELECT * FROM table_name; INSERT INTO table_name (column1, column2) VALUES ...read more

Normalization in SQL is the process of organizing data in a database to reduce redundancy and improve data integrity.

• Normalization involves breaking down a database into smaller, more manageable tables.

• It helps in reducing data redundancy by storing data in a structured way.

• Normalization ensures data integrity by minimizing the chances of inconsistencies.

• There are different normal forms like 1NF, 2NF, 3NF, etc. to guid

SQL is a programming language used for managing and manipulating relational databases.

• SQL stands for Structured Query Language

• It is used to communicate with databases to perform tasks such as querying data, updating records, and creating tables

• Examples of SQL commands include SELECT, INSERT, UPDATE, DELETE

Join is used to combine rows from two or more tables based on a related column, while Procedure is a set of SQL statements that perform a specific task.

• Join is used to retrieve data from multiple tables based on a related column

• Types of joins include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN

• Procedure is a set of SQL statements stored in the database and executed when called

• Procedures can accept input parameters

SSIS Architecture is a platform for data integration and workflow applications.

• SSIS stands for SQL Server Integration Services

• It includes a data flow engine, control flow engine, and event handling

• SSIS packages can be created using SQL Server Data Tools (SSDT)

• SSIS packages can be scheduled and executed using SQL Server Agent

Transactions in SSIS can be implemented using the TransactionOption property in Control Flow tasks.

• Set the TransactionOption property to Required on the Control Flow tasks that need to be included in the transaction.

• Use the TransactionOption property to specify the level of transaction support needed for each task.

• Transactions can be managed using the Distributed Transaction Coordinator (DTC) service.

Use the INSERT INTO statement with multiple value sets separated by commas

• Use the INSERT INTO statement followed by the table name

• List the column names in parentheses after the table name

• Use the VALUES keyword followed by multiple value sets in parentheses, separated by commas

• Example: INSERT INTO table_name (column1, column2) VALUES (value1, value2), (value3, value4)

Update query using joins in SQL

• Use UPDATE statement with JOIN clause to update data in multiple tables

• Specify the tables to be updated and joined using ON clause

• Set the columns to be updated in SET clause