Exam Based Questions and Answers
Hi, welcome and thank for learning continue my all topic well in this post we are sharing most popular questions during the exam based, so before going to exam prepare this question may be better to help for your center. So lets go and start now:
What are the advantages and disadvantages of DBMS?
Ans: We are known about DBMS is a store types of components but there is a one conditions store data but structure way that call management of database system, but what is advantage and disadvantage this is major issue. so lets break in simple way in our language.
Advantage of DBMS
Controls Databases redundancy: All the data is stored in one place, and that recorded in the databases (MySQL) and hence controls the redundancy in the database.
Data Sharing: DBMS allows users with authority to share the data in the database with multiple users.
Easy Maintenance: The centralized nature of the databases helps in the easy maintenance of the data.
Reduce Time: : It reduces the maintenance need and development time.
Backup: It automatically backs up data to maintain its integrity in case of failure.
Multiple User Interface: It offers a number of user interfaces to multiple users.
Disadvantage of DBMS
Cost of Software and hardware: It requires a number of high powered processors and large size memory to run DBMS.
Size: A large amount of storage size is required to run DBMS efficiently.
Complexity : DBMS adds an additional layer complexity to the data.
Higher Impact of Failure: DBMS faces a higher risk of losing the data since all the data is stored at a single location and a catastrophic failure can wipe it all.
Explain the various keys in DBMS?
Ans: Well basically different types of DBMS keys let's break
Candidate Key: The candidate keys in a table are defined as the set of keys that is minimal and can uniquely identify any data row in the table.
Primary Key: - The primary key is selected from one of the candidate keys and becomes the identifying key of a table. It can uniquely identify any data row of the table.
Super Key: - Super Key is the superset of primary key. The super key contains a set of attributes, including the primary key, which can uniquely identify any data row in the table.
Composite Key: - If any single attribute of a table is not capable of being the key i.e. it cannot identify a row uniquely, then we combine two or more attributes to form a key, this is known as a composite key.
Secondary Key:- Only one of the candidate keys is selected as the primary key. The rest of them are known as secondary keys.
Foreign Key:- A foreign key is an attribute value in a table that acts as the primary key in another table. Hence, the foreign key is useful in linking together two tables. Data should be entered in the foreign key column with great care, as wrongly entered data can invalidate the relationship between the two tables.
What are the advantages of file processing systems over DBMS.
Ans: A “file system” is the structure and logic rules that are used to organize groups of data and their names. Files can be collectively present inside a directory. Directories can again be present inside another directory giving it a hierarchical structure. Although Windows supports a variety of file systems, NTFS is the most popular in today’s world. Because files are commonly organized in a hierarchy, the file system allows you to browse the files in the current directory.
Following are some features of the File Systems:
Space Management – File systems allot space on a device in variable block sizes, usually several physical units. The file system is in charge of organizing files and directories, as well as keeping track of which media areas belong to which file and which do not.
When a file is not an exact multiple of the allocation unit, this results in unused space known as slack space. The average unused space for a 512-byte allotment is 256 bytes. The average unused space for 64 KB clusters is 32 KB. When a file system is constructed, the size of the allocation unit is chosen. The quantity of unused space can be reduced by determining the allocation size based on the average size of the files expected to be in the file system.
Hierarchical Data Management – Directories in file systems allow users to organize files into different groupings. This can be accomplished by linking the file name to a table of contents index or an node in a Unix-like file system. Flat (i.e. linear) directory structures are possible, as are hierarchies in which directories can have sub-directories.
Metadata Management – Some extra information pertaining to each file is stored in a file system. A file system keeps all of the metadata connected with a file distinct from the contents of the file, such as the file name, the length of the contents of a file, and the file’s location in the folder hierarchy.
The names of all the files in a directory are usually recorded in a single place—the directory table for that directory—which is generally stored like any other file. Many file systems save only a portion of a file’s metadata in the directory table, while the rest is stored in an entirely distinct structure, such as the node.
Integrity Management – One of a file system’s most important responsibilities is to ensure that the file system structures in secondary storage stay consistent regardless of how programs access the file system. This comprises measures executed if a program that modifies the file system stops abnormally or fails to notify the file system that its tasks have been finished. This could include updating metadata, directory entries, and any data that has been buffered but not yet updated on actual storage media.
Restricting access to Files – To control data access, file systems employ a number of approaches. The goal is usually to block a user or group of users from accessing or changing files. Another reason is to ensure that data is modified in a controlled manner, allowing access to a specific program to be restricted. Passwords saved in the file’s metadata or elsewhere, as well as file permissions in the form of permission bits, access control lists, or capabilities, are examples.
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