Relational Database Management Systems

The statement "Primary key will not be unique" is incorrect. In a database, a primary key is a unique identifier for each record in a table. It ensures that there are no duplicate values in the primary key column. Therefore, by definition, a primary key must be unique. Hence, the correct answer is False.

Foreign Key is used to maintain referential integrity. Referential integrity ensures that the relationships between tables in a database are maintained correctly. It ensures that the foreign key values in a table correspond to the primary key values in another table. This helps in maintaining data consistency and preventing inconsistencies or errors in the database.

Commit is not a DML (Data Manipulation Language) statement. DML statements are used to manipulate data in a database, such as inserting, updating, or deleting records. However, commit is a DDL (Data Definition Language) statement that is used to permanently save changes made within a transaction. It is used to end a transaction and make all the changes made within that transaction permanent.

A DBMS, or Database Management System, is indeed a collection of interrelated data and programs. It is designed to manage, store, retrieve, and manipulate data in a structured manner. The data in a DBMS is organized into tables, which are interconnected through relationships. The programs in a DBMS allow users to interact with the data, perform queries, and carry out various operations such as adding, modifying, or deleting data. Therefore, the statement "A DBMS is a collection of interrelated data & programs" is true.

The main components of client-server architecture include a communication network, which allows the client and server to communicate and exchange data, a server that provides services and resources to the clients, and application software that runs on both the client and server sides. All of these components are essential for the functioning of a client-server architecture.

The correct answer is "Type of relationship." The mapping of a relationship depends on the type of relationship that exists between entities. Different types of relationships, such as one-to-one, one-to-many, or many-to-many, may require different mapping techniques. The type of relationship determines how the relationship is represented in the database, such as through foreign keys or join tables. Therefore, understanding the type of relationship is crucial in determining how to map and represent the relationship in the database.

The SELECT operation in SQL is considered a data query language because it is used to retrieve data from a database. It allows users to specify the columns and rows they want to retrieve, as well as apply filtering and sorting conditions. The SELECT statement does not modify the data or the structure of the database, it only retrieves the desired information. Therefore, it falls under the category of a data query language.

Scattered fragmentation does not exist. Scattered fragmentation refers to the situation where data is scattered randomly throughout the storage device. However, in reality, this type of fragmentation does not occur as it would make data retrieval extremely difficult and inefficient. Instead, fragmentation typically occurs in the form of horizontal, vertical, or mixed fragmentation, where data is divided into smaller pieces based on certain criteria such as rows, columns, or a combination of both.

The lowest known value for maximum cardinality is 1 because cardinality refers to the number of elements in a set. A set with a maximum cardinality of 1 means it can only have one element.

Regular entities are not existence dependent on other entities. This means that regular entities can exist independently and do not rely on the existence of any other entities. They have their own unique identity and can be accessed and manipulated separately. Unlike weak entities, which depend on the existence of a related entity for their own existence, regular entities can stand alone and have their own attributes and relationships.

A super key is a set of one or more attributes that can uniquely identify a record in a database table. It may contain additional attributes besides the minimum required to uniquely identify a record. Therefore, a candidate key, which is a minimal super key, can be chosen from a super key. The primary key is a specific candidate key that is chosen as the main identifier for a table. Surrogate keys are artificially generated keys used when there is no natural key available. Composite keys are keys that are made up of multiple attributes.

A one-to-one relationship is rarely seen in real life because it implies that for every one entity in the first set, there is only one corresponding entity in the second set, and vice versa. In most real-life scenarios, relationships tend to be more complex and involve multiple entities on either side. For example, in a marriage, one person can have multiple siblings, friends, and colleagues, creating a one-to-many or many-to-many relationship. Similarly, in a company, one manager can have multiple employees, resulting in a many-to-one relationship.

A relation is in NF (Normal Form) if it does not have any repeating group. This means that all the attributes in the relation are functionally dependent on the primary key, and there are no groups of attributes that can be repeated. Therefore, the correct answer is False, as a relation is in NF if it does not have any repeating group.

Grant and Revoke commands are categorized under Data Control Language (DCL). DCL is a subset of SQL (Structured Query Language) that is used to control access to the database and manage permissions. Grant command is used to give users certain privileges or permissions to perform specific actions on the database objects, while Revoke command is used to remove or revoke those privileges. DCL commands are primarily used by database administrators to control and manage user access and security within the database system.

The statement is false because it was not ANSI that created a Database task group to develop a set of standards for Database Systems. It was actually the American National Standards Institute (ANSI) that created the SQL (Structured Query Language) standard for Database Systems.

The statement is false because the internal query representation is not always a binary tree. There are various ways to represent a query internally, such as using a graph data structure or a linear representation. The choice of representation depends on the specific requirements and constraints of the system or algorithm being used.

The term "non procedural" refers to a type of programming language or approach that does not require the programmer to specify the exact steps or sequence of operations to achieve a desired outcome. In the context of SQL (Structured Query Language), it is considered non procedural because it focuses on specifying what data is needed rather than how to retrieve it. SQL statements are declarative, meaning they describe the desired result without specifying the exact steps to achieve it. This allows for a more flexible and efficient approach to querying and manipulating data in a database.

2PC stands for Two-Phase Commit, which is a recovery management technique in DBMS. It ensures that all the participating databases in a distributed transaction either commit or rollback the transaction as a whole. In the first phase, the coordinator sends a prepare message to all the participants, and they respond with either a vote to commit or abort. In the second phase, the coordinator sends a commit or abort message based on the participants' votes. This ensures the atomicity and consistency of distributed transactions, making it a crucial recovery management technique in DBMS.

E.F. Codd is credited with first developing the process of normalization. He was a computer scientist who introduced the concept of relational databases and proposed a set of rules for organizing data efficiently. His work revolutionized the field of database management systems and laid the foundation for modern data normalization techniques. Codd's contributions have had a significant impact on the design and functionality of databases, making them more structured, scalable, and easier to manage.