SQL MCQ Questions: Here you will get selected & important objective type MCQs on SQL SQL (Structured Query Language) quiz question bank in PDf format for APTITUDE TESTS - MENTAL ABILITY - SOLVED OBJECTIVE MCQ SETS. This SQL aptitude contains 28 questions with answers. We also attached the pdf file for the SQL aptitude Questions. Feel free to download the. RDBMS stands for Relational Database Management System. RDBMS store the data into the collection of tables, which is related by common.
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SQL Basic Aptitude Questions and Answers - This section contains Aptitude Questions on SQL Basics - SQL Commands, syntaxes, examples, definitions etc. This is the database questions and answers section on "Introduction to SQL" with download Database Introduction to SQL quiz questions with answers as PDF. Technical Aptitude questions with answers PDF download for "SQL". This download file includes SQL query programs and program error codes. Download this.
ADD B. Aggregate — max , count - Calculated with respect to numeric. ASCII value can be used to compare these character data. Right join return rows which are common between the tables and all rows of Right hand side table. A view is a virtual table which consists of a subset of data contained in a table. What is normalization? How to fetch alternate records from a table?
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Both A and B are correct. Neither A nor B are correct. Option B Explanation: Which of the following is the original purpose of SQL? To specify the syntax and semantics of SQL data definition language B. To specify the syntax and semantics of SQL manipulation language C. To define the data structures D.
If you spot any typographical, grammatical or factual error in our site, then please let us know. Thanks in advance. Option C. Option A. Option B. Which data manipulation command is used to combines the records from one or more tables? Answer A. JOIN D. Option C Show Answer. Which of the following is not a valid SQL type? The main aim of Normalization is to add, delete or modify field that can be made in a single table. What is Denormalization. DeNormalization is a technique used to access the data from higher to lower normal forms of database.
It is also process of introducing redundancy into a table by incorporating data from the related tables. What are all the different normalizations? The normal forms can be divided into 5 forms, and they are explained below -. First Normal Form 1NF:. This should remove all the duplicate columns from the table.
Creation of tables for the related data and identification of unique columns. Second Normal Form 2NF:. Meeting all requirements of the first normal form. Placing the subsets of data in separate tables and Creation of relationships between the tables using primary keys. Third Normal Form 3NF:. This should meet all requirements of 2NF.
Removing the columns which are not dependent on primary key constraints. Fourth Normal Form 3NF:. Meeting all the requirements of third normal form and it should not have multi- valued dependencies. What is a View? A view is a virtual table which consists of a subset of data contained in a table. Views are not virtually present, and it takes less space to store.
View can have data of one or more tables combined, and it is depending on the relationship. What is an Index?
An index is performance tuning method of allowing faster retrieval of records from the table. An index creates an entry for each value and it will be faster to retrieve data. What are all the different types of indexes? There are three types of indexes -. Unique Index. This indexing does not allow the field to have duplicate values if the column is unique indexed. Unique index can be applied automatically when primary key is defined. Clustered Index. This type of index reorders the physical order of the table and search based on the key values.
Each table can have only one clustered index. NonClustered Index. NonClustered Index does not alter the physical order of the table and maintains logical order of data. Each table can have nonclustered indexes. What is a Cursor? A database Cursor is a control which enables traversal over the rows or records in the table.
This can be viewed as a pointer to one row in a set of rows.
Cursor is very much useful for traversing such as retrieval, addition and removal of database records. What is a relationship and what are they?
Database Relationship is defined as the connection between the tables in a database. There are various data basing relationships, and they are as follows:. One to One Relationship. One to Many Relationship. Many to One Relationship. Self-Referencing Relationship. What is a query? A DB query is a code written in order to get the information back from the database.
Query can be designed in such a way that it matched with our expectation of the result set. Simply, a question to the Database. What is subquery?
A subquery is a query within another query. The outer query is called as main query, and inner query is called subquery. SubQuery is always executed first, and the result of subquery is passed on to the main query. What are the types of subquery? There are two types of subquery — Correlated and Non-Correlated.
A correlated subquery cannot be considered as independent query, but it can refer the column in a table listed in the FROM the list of the main query.
A Non-Correlated sub query can be considered as independent query and the output of subquery are substituted in the main query. What is a stored procedure? Stored Procedure is a function consists of many SQL statement to access the database system. Several SQL statements are consolidated into a stored procedure and execute them whenever and wherever required.
What is a trigger? A DB trigger is a code or programs that automatically execute with response to some event on a table or view in a database.
Mainly, trigger helps to maintain the integrity of the database. When a new student is added to the student database, new records should be created in the related tables like Exam, Score and Attendance tables. Commit and Rollback can be performed after delete statement. Truncate operation cannot be rolled back. What are local and global variables and their differences? Local variables are the variables which can be used or exist inside the function.
They are not known to the other functions and those variables cannot be referred or used. Variables can be created whenever that function is called.
Global variables are the variables which can be used or exist throughout the program. Same variable declared in global cannot be used in functions.