1) Define Database. A prearranged collection of figures known as data is called database. 2) What is DBMS? Database Management Systems. RDBMS stands for Relational Database Management System. RDBMS store the data into the collection of tables, which is related by common. SQL, PLSQL, Oracle, Oracle DBA, SQL Server Interview Questions and Answers Pdf for Freshers or bestthing.info interview section questions contains a.
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Top 50 Basic SQL Interview Questions And Answers Pdf. 2. Explain SQL Data Types? Answer: In SQL Server, each column in a database table has a name and . Database questions and answers with explanation for interview, competitive can download Database quiz questions with answers as PDF files and eBooks. SQL Interview Questions with Answers bestthing.info What is RDBMS? Relational Data Base Management Systems (RDBMS) are database.
Ans: Entity can be anything, be it a place, class or object which has an independent existence in the real world. Entity type represents a set of entities which have similar attributes. Entity set in the database represents a collection of entities having a particular entity type. Q 24 Define Weak Entity set. Ans: Weak entity set is the one whose primary key comprises of its partial key as well as the primary key of its parent entity. This is the case because the entity set may not have sufficient attributes to form a primary key.
Relation is a two-dimensional table containing a number of rows and columns where every row represents a record of the relation. Ans: VDL is View Definition language which represents user views and their mapping to the conceptual schema. Q 27 Define Cursor and its types.
Ans: Cursor is a temporary work area which stores the data as well as the result set occurred after manipulation of data retrieved. A cursor can hold only one row at a time.
Q 28 What is Database transaction? Ans: Sequence of operation performed which changes the consistent state of the database to another is known as the database transaction. After the completion of the transaction, either the successful completion is reflected in the system or the transaction fails and no change is reflected.
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Q 29 Define Database Lock and its types. Ans: Database lock basically signifies the transaction about the current status of the data item i.
Q 30 What is Data Warehousing? Ans: The storage as well as access to data, that is being derived from the transactions and other sources, from a central location in order to perform the analysis is called Data Warehousing. Q 31 What do you understand by Join?
Ans: Join is the process of explaining the relationship between different tables by combining columns from one or more table having common values in each. When a table joins with itself, it is known as Self Join.
Q 32 What do you understand by Index hunting? Ans: Index hunting is the process of boosting the collection of indexes which help in improving the query performance as well as the speed of the database.
Q 33 How to improve query performance using Index hunting? Ans: Index hunting help in improving query performance by: Using query optimizer to coordinate queries with the workload.
Observing the performance and effect of index and query distribution. Ans: Clustered Index alters the table and reorders the way in which the records are stored in the table. Data retrieval is made faster by using the clustered index. A Non-clustered index does alter the records that are stored in the table but creates a completely different object within the table.
Q 35 What are the disadvantages of a Query?
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Ans: Disadvantages of a Query are: Indexes are not present. Stored procedures are excessively compiled. Difficulty in interfacing. Q 36 What do you understand by Fragmentation? Ans: Fragmentation is a feature which controls the logical data units, also known as fragments that are stored at different sites of a distributed database system.
Q 37 Define Join types. This SQL query returns result from both the tables having a common value in rows. This returns all the rows as a result from the right table even if the JOIN condition does not match any records in the left table.
This returns all the rows as a result of the left table even if JOIN condition does not match any records in the right table. Ans: Atomicity is the condition where either all the actions of the transaction are performed or none. This means, when there is an incomplete transaction, database management system itself will undo the effects done by the incomplete transaction. Aggregation is the concept of expressing the relationship with the collection of entities and their relationships.
Q 39 Define Phantom deadlock. Ans: Phantom deadlock detection is the condition where the deadlock does not actually exist but due to a delay in propagating local information, deadlock detection algorithms identify the deadlocks.
Q 40 Define checkpoint. Ans: Checkpoint declares a point before which all the logs are stored permanently in the storage disk and is the inconsistent state. In the case of crashes, the amount of work and time is saved as the system can restart from the checkpoint. Q 41 What is Database partitioning? Ans: Database partitioning is the process of partitioning tables, indexes into smaller pieces in order to manage and access the data at a finer level.
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This process of partitioning reduces the cost of storing a large amount of data as well as enhances the performance and manageability. Q 42 Explain the importance of Database partitioning. Ans: The importance of Database partitioning are: Improves query performance and manageability. Simplifies common administration tasks.
Acts as a key tool for building systems with extremely high availability requirements.
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Allows accessing a large part of a single partition. Q 43 Explain Data Dictionary. Ans: Data dictionary is a set of information describing the content and structure of the tables and database objects.
The job of the information stored in the data dictionary is to control, manipulate and access the relationship between database elements. Ans: Primary key is that column of the table whose every row data is uniquely identified.
Every row in the table must have a primary key and no two rows can have the same primary key. Primary key value can never be null nor can be modified or updated. Composite Key is a form of the candidate key where a set of columns will uniquely identify every row in the table. Q 45 What do you understand by Unique key? Ans: A Unique key is same as the primary key whose every row data is uniquely identified with a difference of null value i.
Unique key allows one value as NULL value. Q 46 What do you understand by Database Triggers? Q 47 Define Stored procedures. Ans: A Stored procedure is a collection of pre-compiled SQL Queries, which when executed denotes a program taking input, process and gives the output.
Q 48 What do you understand by B-Trees? Ans: B-Tree represents the data structure in the form of a tree for external memory that reads and writes large blocks of data.
It is commonly used in databases and file systems where all the insertions, deletions, sorting, etc. The difference between the clustered and non-clustered index in SQL is as follows: Clustered Index: It is used for easy retrieval of data from the database and it is faster. One table can only have one clustered index It alters the way records are stored in a database as it sorts out rows by the column which is set to be clustered index.
Non-Clustered Index: It is slower compared to the Clustered index. What is a View? A view is like a subset of a table which is stored logically in a database. A view is a virtual table. It contains rows and columns similar to a real table. The fields in the view are fields from one or more real tables. Views do not contain data of their own. They are used to restrict access to the database or to hide data complexity. What are the advantages of Views? Some of the advantages of Views are Views occupy no space Views are used to simply retrieve the results of complicated queries that need to be executed often.
Views are used to restrict access to the database or to hide data complexity. What is a relationship and what are they? Database Relationship is defined as the connection between the tables in a database. There are various database relationships namely 1.
One to One Relationship 2. One to Many Relationship 3. Many to One Relationship 4. Self-Referencing Relationship What is a query?
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A database query is a request for data or information from a database table or combination of tables. A database query can be either a select query or an action query. What is a Subquery? A Subquery is a SQL query within another query.
It is a subset of a Select statement whose return values are used in filtering the conditions of the main query. What are the types of subquery? There are two types of subquery: 1. Correlated: In a SQL database query, a correlated subquery is a subquery that uses values from the outer query in order to complete.
Because a correlated subquery requires the outer query to be executed first, the correlated subquery must run once for every row in the outer query. It is also known as a synchronized subquery.
Non-Correlated: A Non-correlated subquery is a subquery in which both outer query and inner query are independent to each other. What is Synchronized Subquery? Refer Correlated Subquery.Analysis Phase.
Indeed it helps to do a self evaluatio. ALTER objecttype objectname parameters. Declared automatically as soon as the execution of SQL takes place without the awareness of the user. Japanese Kana characters. Executes the specified pass-through query on the specified linked server. You are not liable to change any computed value in any particular view. It can be defined as being a 'thing' with an independent existence in the real world.
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