hakdog

Question 1

A column or group of columns in a table that uniquely identify every row in that table.

Answer 1

Primary key

Question 2

Defines the number of entities in one entity set, which can be associated with the number of entities of other set via relationship set.

Answer 2

Cardinality

Question 3

One entity from entity set A can be associated with at most one entity of entity set B and vice versa.

Answer 3

One-to-one

Question 4

One entity from entity set A can be associated with more than one entities of entity set B however an entity from entity set B, can be associated with at most one entity.

Answer 4

One-to-many

Question 5

More than one entities from entity set A can be associated with at most one entity of entity set B, however an entity from entity set B can be associated with more than one entity from entity set A.

Answer 5

Many-to-one

Question 6

One entity from A can be associated with more than one entity from B and vice versa.

Answer 6

Many-to-many

Question 7

One entity from A can be associated with more than one entity from B and vice versa.

Answer 7

Many-to-many

Question 8

Each entity is involved in the relationship. It is represented by double lines.

Answer 8

Total participation

Question 9

Not all entities are involved in the relationship. It is represented by single lines.

Answer 9

Partial participations

Question 10

It has the power of expressing database entities in a conceptual hierarchical manner.

Answer 10

ER Model

Question 11

The process of generalizing entities, where the generalized entities contain in the properties of all the generalized entities. A number of entities are brought together into one generalized entity based on their similiar characteristics.

Answer 11

Generalization

Question 12

A group of entities is divided into sub-groups based on their characteristics. Take a group ‘person’ for example

Answer 12

Specialization

Question 13

It is an important feature of generalization and specialization. It allows lover level of entities to inherit the attributes of higher level entities.

Answer 13

Inheritance

Question 14

The data stored in database, may it be user data or metadata, must be a value of some table cell.

Answer 14

Rule 1: Information Rule

Question 15

Every single data element (value) is a guaranteed to be accessible logically with a combination of table-name, primary key (row value), and attribute name (column name)

Answer 15

Rule 2: Guaranteed Access Rule

Question 16

The NULL values in a database must be given a systematic and uniform treatment. This is a very important rule because a NULL can be interpreted as one the following − data
is missing, data is not known, or data is not applicable.

Answer 16

Rule 3: Systematic Treatment of Null Values

Question 17

The structure description of the entire database must be stored in an online catalog, known as data dictionary, which can be accessed by authorized users.

Answer 17

Rule 4: Active online catalog

Question 18

A database can only be accessed using a language having linear syntax that support data definition, data manipulation, and transaction management operations.

Answer 18

Rule 5: Comprehensive Data sub-language rule

Question 19

All the views of a database, which can theoretically be updated, must also be updatable by the system.

Answer 19

Rule 6: View Updating Rule

Question 20

A database must support high-level insertion,
updation, and deletion.

Answer 20

Rule 7: High-Level Insert, Update, and Delete Rule

Question 21

The data stored in a database must be independent of the
applications that access the database. Any change in the physical structure of a database must not have
any impact on how the data is being accessed by external applications.

Answer 21

Rule 8: Physical Data Independence

Question 22

The logical data in a database must be independent of its user’s
view (application). Any change in logical data must not affect the applications using it.

Answer 22

Rule 9: Logical Data Independence

Question 23

The end-user must not be able to see that the data is distributed
over various locations. Users should always get the impression that the data is located at one site only.

Answer 23

Rule 11: Distribution Independence

Question 24

A database must be independent of the application that uses it. All its
integrity constraints can be independently modified without the need of any change in the application.

Answer 24

Rule 10: Integrity Independence

Question 25

If a system has an interface that provides access to low-level records,
then the interface must not be able to subvert the system and bypass security and integrity constraints.

Answer 25

Rule 12: Non-Subversion Rule

Question 26

The main highlights of this model are Data is stored in tables called relations, Relations can be normalized, In normalized relations, values saved are atomic values, Each row in relation contains unique value, Each column in relation contains values from a same domain.

Answer 26

Relational Model

Question 27

In relationaldata model, relations are saved in the format of Tables. This format stores the relation among entities. A table has rows and columns, where rows represents records and columns represent the
attributes.

Answer 27

Table

Question 28

A single row of a table, which contains a single record for that relation.

Answer 28

Tuple

Question 29

A finite set of tuples in the relational database
system represents ______

Answer 29

Relation Instance

Question 30

It describes the relation name (table name),
attributes, and their names

Answer 30

Relation Schema

Question 31

Each row has one or more attributes, known as
_______ , which can identify the row in the relation (table) uniquely.

Answer 31

Relation Key

Question 32

Every attribute has some pre-defined value scope

Answer 32

Attribute Domain

Question 33

Every relation has some conditions that must hold for it to be a valid relation. These conditions are called _______ .

Answer 33

Relational Integrity Constraints

Question 34

There must be at least one minimal subset of attributes in the relation, which can identify a tuple
uniquely. This minimal subset of attributes is called ___ for that relation.

Answer 34

Key

Question 35

If there are more than one such minimal subsets, these are called _________

Answer 35

Candidate Keys

Question 36

It is a key used to link two tables together.

Answer 36

Foreign Key

Question 37

It is a field (or collection of fields) in one table that
refers to the PRIMARY KEY in another table.

Answer 37

Foreign Key

Question 38

The table containing the foreign key is called the

Answer 38

Child Table

Question 39

The table containing the candidate key is called the

Answer 39

Referenced or parent
table