Entity-relationship Diagram! Database Trivia Quiz

The most important hardware component for the operation of a database management system is a high speed large capacity disk. This is because a database management system requires a large amount of storage space to store and retrieve data efficiently. A high speed disk ensures fast access and retrieval of data, while a large capacity disk allows for the storage of a large amount of data. Without a high speed large capacity disk, the performance of the database management system would be significantly hindered.

Metadata refers to the information about data in a database. It includes details such as the structure, format, and organization of the data, as well as information about its source, meaning, and usage. Metadata provides context and helps in understanding and managing the data effectively. It is used for data integration, data governance, data quality, and other data management processes. Hyperdata and Teradata are not valid terms related to the information about data in a database. Therefore, the correct answer is Metadata.

The ER model includes additional concepts like specialization, generalization, and categorization. Specialization is the process of defining subclasses based on a superclass, allowing for more specific attributes and relationships. Generalization is the opposite process, where common attributes and relationships are identified and grouped into a superclass. Categorization is the process of organizing entities into categories or classes based on their common characteristics. Therefore, all of the given options are correct as they represent additional concepts included in the ER model.

A data dictionary is a special file that contains all the mentioned information. It includes the names of all fields in all files, the data types of all fields in all files, and the widths of all fields in all files. The data dictionary serves as a reference guide for understanding the structure and organization of the data stored in a database or system. It helps in ensuring consistency and accuracy in data management by providing a centralized source of information about the data elements used in the system.

The highest level in the hierarchy of data organization is called a database. A database is a collection of related data that is organized and stored in a structured manner. It allows for efficient storage, retrieval, and manipulation of data. At the highest level, a database contains multiple tables or files, which in turn contain records and fields. It provides a centralized and integrated approach to managing data, ensuring data consistency and security.

The IS NULL operator tests a column for the absence of data. It is used to check if a column contains a NULL value, which represents the absence of data. Therefore, the IS NULL operator is the correct answer for this question.

In a one-to-many relationship, the entity that is on the one side of the relationship is called a Parent entity. This entity is the main entity that has a relationship with multiple instances of another entity, known as the Child entity. The Parent entity acts as the "one" in the relationship, while the Child entity represents the "many" side. The Parent entity typically holds the primary key that is used to establish the relationship with the Child entities.

E-R modelling techniques is a top-down approach because it starts with identifying the overall structure and then breaks it down into smaller components. In this approach, the focus is on understanding the system as a whole and then gradually refining the details. It involves identifying the entities, their relationships, and attributes, and then creating the entity-relationship diagram accordingly. This approach allows for a systematic and organized way of designing the database by starting from a high-level perspective and gradually moving towards the implementation details.

The relationship used to represent a specialization entity is ISA. This relationship signifies that one entity is a specialized version of another entity. It is commonly used in database design to represent inheritance and hierarchy in entities.

The given information states that every time attribute A appears, it is matched with the same value of attribute B, but not the same value of attribute C. This implies that there is a direct relationship between A and B, where A determines the value of B. However, there is no information provided about the relationship between A and C or between B and C. Therefore, the only valid conclusion that can be drawn is that A determines the value of B, making the statement A → B true.

The ALTER TABLE command is used in SQL to change a table's storage characteristics. This command allows modifications to be made to an existing table, such as adding or dropping columns, changing data types, or altering constraints. The MODIFY TABLE and CHANGE TABLE options are not valid SQL commands for changing a table's storage characteristics. Therefore, the correct answer is ALTER TABLE.

The 3NF (Third Normal Form) is considered adequate for normal relational database design. This normal form ensures that there are no transitive dependencies between non-key attributes in a relation. It helps in reducing data redundancy and improving data integrity by eliminating any fields that are not directly dependent on the primary key. By achieving 3NF, a database design can efficiently organize and store data while minimizing data redundancy and maintaining data consistency.

Two phase locking is a protocol that ensures serializability of transactions. It consists of two phases: the growing phase and the shrinking phase. In the growing phase, transactions acquire locks on the resources they need before accessing them. This ensures that no other transaction can access the same resource simultaneously. In the shrinking phase, transactions release the locks they acquired, allowing other transactions to access the resources. By following this protocol, the transactions are executed in a serial order, preventing conflicts and ensuring serializability.

The correct answer is the first option: SELECT city, temperature, condition FROM weather WHERE condition NOT IN ('sunny', 'cloudy'). This query retrieves the names of cities along with their temperature and condition from the weather table. The condition is filtered to exclude both 'sunny' and 'cloudy', meaning that only cities with conditions other than sunny or cloudy will be included in the result.

The given scenario describes the "Wait-die" strategy for handling conflicting transactions. In this strategy, if a transaction Ti requests a data item currently held by Tj, Ti is allowed to wait only if it has a smaller timestamp (i.e., it is older) than Tj. If Ti has a larger timestamp (i.e., it is younger) than Tj, Ti is rolled back (dies). This strategy ensures that older transactions are given priority and prevents deadlock situations.

Immediate database modification technique uses both undo and redo. Undo is used to rollback or undo the changes made to the database in case of a failure or error. Redo is used to reapply the changes made to the database after a failure or error has been corrected. By using both undo and redo, the database can maintain consistency and integrity even in the event of failures or errors.

In an E-R diagram, the double line represents total participation by entities. Total participation means that every entity in one entity set must participate in a relationship with an entity in another entity set. The double line indicates that the participation is mandatory and every entity must be involved in the relationship. This is in contrast to a single line, which represents partial participation, where some entities may choose not to participate in the relationship.

The traditional approach to information processing does not involve common sharing of data among various applications. In this approach, each application has its own separate data files and does not share data with other applications. This lack of data sharing can lead to data redundancy and inconsistency.

If every functional dependency in set E is also in the closure of F, it means that the closure of F contains all the functional dependencies in E. This implies that F is able to derive all the functional dependencies in E. Therefore, E is covered by F.

In a two-phase locking protocol, the transaction releases locks in the shrinking phase. This phase occurs after the transaction has completed its operations and is ready to release the locks it acquired during the growing phase. During the shrinking phase, the transaction releases the locks in a systematic manner, ensuring that other transactions can access the locked resources. This helps in maintaining data consistency and preventing conflicts between concurrent transactions.

The constraint that the sum of the accounts x and y should remain constant is that of consistency. Consistency ensures that the data in the database remains in a valid state before and after the transaction. In this case, the transaction involves deducting 50 from account x and adding 50 to account y. To maintain consistency, the sum of the balances in both accounts should remain the same before and after the transaction.

A unit of storage that can store one or more records in a hash file organization is denoted as "Buckets". In a hash file organization, data is stored in buckets, which are essentially containers that hold multiple records. Each bucket is identified by a unique hash value, allowing for efficient retrieval and storage of records based on their key values. Buckets are commonly used in hash table data structures to store and retrieve data quickly using a hashing algorithm.

Adding appropriate attributes to a weak entity set can convert it into a strong entity set. Weak entity sets depend on a strong entity set for their existence and cannot exist independently. By adding appropriate attributes, the weak entity set becomes capable of existing independently and no longer relies on another entity set for its existence. This strengthens the entity set and converts it into a strong entity set. Generalization and aggregation are not methods for converting weak entity sets into strong entity sets.

A functional dependency is a relationship between attributes in a database. It states that the value of one or more attributes determines the value of another attribute. In other words, if we know the value of certain attributes, we can determine the value of other attributes based on this relationship. Therefore, the correct answer is "Attributes" because functional dependencies are defined between attributes, not tables, rows, or relations.

The given correct answer is "Isolation." Isolation refers to the property of a database system that ensures that transactions are executed in a way that they are not affected by other concurrently executing transactions. It ensures that each transaction is executed independently and in isolation from other transactions, preventing interference and maintaining data integrity. Isolation is important to prevent issues like dirty reads, non-repeatable reads, and phantom reads, which can occur when multiple transactions access and modify the same data simultaneously.

The Two Phase Lock (2PL) protocol is a procedure for acquiring locks in a transaction where all necessary locks are acquired before any are released. In the 2PL protocol, a transaction is divided into two phases: the growing phase and the shrinking phase. In the growing phase, the transaction acquires all the necessary locks before it starts accessing and modifying the data. Once the transaction has acquired all the necessary locks, it enters the shrinking phase where it starts releasing the locks only after it has completed all its data access and modification operations. This ensures that no conflicts occur between transactions and maintains data integrity.

A disjointness constraint requires that an entity belong to no more than one lower-level entity set. This means that an entity cannot simultaneously belong to multiple lower-level entity sets. This constraint ensures that there is no overlap or duplication of entities across different entity sets, maintaining the integrity and uniqueness of the data model.

The default completeness constraint is partial. This means that if no constraint is specified, it is assumed that the generalization or specialization is only partial, meaning that not all instances of the superclass will have corresponding instances in the subclass.

Deadlock refers to a situation where multiple transactions are waiting indefinitely for each other to release the resources they hold. In this scenario, a transaction holds a data item and is waiting for the release of the data item held by another transaction. However, that transaction is also waiting for yet another transaction, creating a cycle of dependencies and preventing any progress. This deadlock situation can cause a system to become unresponsive and requires intervention to resolve.

The correct answer is "Create temporary table". When the "Create temporary table" command is used, the tables created are only available within the transaction executing the query. These temporary tables are dropped automatically when the transaction finishes, ensuring that they do not persist beyond the scope of the transaction.

The current copy of the database is identified by a pointer called "Db-pointer" which is stored on disk. This pointer helps in locating and accessing the latest version of the database. It serves as a reference or address to the database file, allowing users or applications to retrieve and manipulate the data effectively.

Clustering file organization allows us to read records that would satisfy the join condition by using one block read. In this type of file organization, related records are physically stored together in the same block or nearby blocks on the disk. This reduces the number of disk accesses required to retrieve the records needed for a join operation, resulting in improved performance.

The DBMS acts as an interface between the database application and the database. The database application is responsible for interacting with the user and performing various operations on the data stored in the database. The DBMS acts as a mediator between the application and the database, allowing the application to send requests to the database and retrieve the required data. It also handles tasks such as data storage, retrieval, security, and concurrency control, ensuring efficient and reliable access to the database for the application.

The correct answer is Entity-relationship diagram. An entity-relationship diagram is a graphical representation of the logical structure of a database. It shows the entities (objects or concepts) in the database, their attributes, and the relationships between them. This diagram helps to visualize the overall structure of the database and how different entities are connected to each other. An entity diagram, on the other hand, may refer to a diagram that represents only the entities in the database without showing the relationships between them. Therefore, the correct answer is Entity-relationship diagram.

RAID level 1 refers to disk mirroring with block striping. In this level of RAID, data is mirrored onto two or more disks simultaneously, providing redundancy and fault tolerance. Each disk in the array contains an exact copy of the data, allowing for data recovery in case of disk failure. Block striping is also used, which means that data is divided into blocks and distributed across the disks in the array. This combination of mirroring and striping provides both data protection and improved performance.

This answer is correct because it selects both the city and temperature columns from the weather table and orders the results in increasing order based on the temperature column. This will give a list of cities sorted by their temperature values from lowest to highest.

The correct answer is "Select year, avg(num credits) over (order by year rows 3 preceding) as avg total credits from tot credits." This is the correct query to compute averages over the 3 preceding tuples in the specified sort order. The "rows 3 preceding" clause specifies that the average should be calculated over the current tuple and the 2 preceding tuples in the sort order of the "year" column.

A tablespace is a logical grouping of database objects, usually to facilitate security, performance, or the availability of database objects such as tables and indexes. It acts as a container for storing data files, which in turn contain the actual data stored in tables and indexes. By organizing database objects into tablespaces, it becomes easier to manage and allocate storage space, control access and permissions, and optimize performance by placing related objects together.

An instance in Oracle is the collection of memory structures and background processes that operate against an Oracle database. It represents the running environment of the database and manages the physical and logical structures of the database. The memory structures include the System Global Area (SGA) which stores data and control information, and the Program Global Area (PGA) which stores data and control information for individual user processes. The background processes perform various tasks such as managing memory, managing transactions, and performing backup and recovery operations. Therefore, the correct answer is Instance.

A non-serial interleaving of T1 and T2 for concurrent execution leads to a schedule that is not conflict serializable. Conflict serializability is a property of a schedule where the order of conflicting operations (operations that access the same data item) is preserved. In this case, both T1 and T2 read and write the same data items P and Q, and their operations conflict with each other. If the schedule is not conflict serializable, it means that the order of conflicting operations is not preserved, leading to potential data inconsistencies.

The highest normal form of this relation schema is 3NF. This is because all the functional dependencies in the schema are either full key dependencies or transitive dependencies. In 3NF, there should be no transitive dependencies, meaning that no non-key attribute should be functionally dependent on another non-key attribute. In this schema, all the functional dependencies are either between the key attributes (name, courseNo, and rollNo) and the non-key attribute (grade), or between the non-key attributes (name and rollNo). Therefore, the schema satisfies the requirements of 3NF.

The given answer is correct because in the Book scheme, the functional dependency I violates the 2NF as it is a partial dependency. By decomposing the scheme, we can remove this partial dependency and achieve 2NF. In the Collection scheme, there are no partial dependencies or transitive dependencies, so it is already in 3NF. Therefore, the statement "Book is in 2NF and Collection is in 3NF" is true.

The relation R has four candidate keys. A candidate key is a minimal set of attributes that can uniquely identify every tuple in a relation. To determine the candidate keys, we can use the closure of each attribute set in R. Starting with each individual attribute, we find the closure by applying the functional dependencies in F. The closure of each attribute set is as follows: A+ = ABCFHG, B+ = BCFHGA, C+ = CFHGA, D+ = D, E+ = AEBCFHG, F+ = FEG, G+ = G, H+ = H. From these closures, we can see that the candidate keys are AD, AE, AF, and AG, as they are the minimal sets of attributes that can determine all other attributes in R. Therefore, the answer is 4.

The given correct answer is "the definition of a view should not have GROUP BY clause in it". This statement is invalid because a view can have a GROUP BY clause in its definition. The GROUP BY clause is used to group rows based on a specific column or columns in the view's underlying query. It is often used in conjunction with aggregate functions to perform calculations on grouped data. Therefore, the statement is incorrect.

A weak entity relationship is represented by a double diamond. A weak entity is an entity that cannot exist without the existence of another entity, known as the identifying entity. The double diamond symbolizes this dependency, indicating that the weak entity relies on the identifying entity for its existence. The double diamond is used to visually represent this relationship in entity-relationship diagrams, making it easier to understand the dependencies between entities.

In a BCNF (Boyce-Codd Normal Form) relation, a prime attribute cannot be transitively dependent on a key. BCNF requires that every non-trivial functional dependency in the relation must be determined by a superkey. Therefore, a prime attribute cannot be transitively dependent on a key in a BCNF relation.

The given relational schema is not in 2NF because it violates the second normal form (2NF) rule which states that no non-prime attribute should be functionally dependent on a proper subset of any candidate key. In this case, attribute E is functionally dependent on C, which is a proper subset of the candidate key AB. Therefore, the relational schema is not in 2NF.

The given relation R has two functional dependencies: ABC -> DE and D -> AB. To find the number of superkeys, we need to consider all possible combinations of attributes that can uniquely determine all other attributes.

From the given functional dependencies, we can see that ABCD is a superkey since it can determine all attributes. Additionally, D is also a superkey as it can determine AB, and ABC is also a superkey as it can determine DE.

Other possible superkeys can be formed by combining attributes from ABCD with attributes from DE. For example, ABCDE is a superkey since it can determine all attributes. Similarly, ABCE, ACDE, BCDE, ABD, ACD, BCD, and ACE are also superkeys.

Therefore, the number of superkeys for relation R is 10.

This table is in 1NF (First Normal Form) because it satisfies the criteria for 1NF. In 1NF, each attribute in a table must contain only atomic values (indivisible values). The given table has fields F1, F2, F3, F4, and F5, and there are no repeating groups or multivalued attributes. Therefore, it meets the requirements for 1NF.

The correct answer is more than zero but less than that of an equivalent 3NF decomposition. When a relation is decomposed into BCNF, it minimizes redundancy by eliminating partial dependencies. However, BCNF does not eliminate all redundancy. There may still be redundancy present due to transitive dependencies. In an equivalent 3NF decomposition, which further eliminates transitive dependencies, the redundancy would be completely eliminated. Therefore, the redundancy in the resulting set of relations from BCNF decomposition is more than zero but less than that of an equivalent 3NF decomposition.