Is an attribute or a combination of attributes that uniquely identifies each row in a relation?

focusNode

Inhaltsverzeichnis Show

Chapter5(LogicalDatabaseDesignAndTheRelationalModel)
Which attribute can uniquely identify a row in a table?
What is an attribute or group of attributes that uniquely identify a tuple in a relation?
Which attribute of a row is called as?
Which of the following can be used to uniquely identify a row?

Didn't know it?
click below

Knew it?
click below

Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

Normal Size Small Size show me how

Chapter5(LogicalDatabaseDesignAndTheRelationalModel)

Question	Answer
The relational data model consists of the following three components:	(1) Data Structure (2) Data manipulation (3) Data integrity
A _____ is a named, two-dimensional table of data.	relation
A _____ is an attribute (or combination of attributes) that uniquely identifies each row in a relation.	primary key
A _____ is designated by underlining the attribute name.	primary key
A _____ is a primary key that consists of more than one attribute.	composite key
A _____ is an attribute (possibly composite) in a relation of a database that serves as the primary key of another relation in the same database.	foreign key
There are three reasons that you should create an instance of your relational schema with sample data.	(1) The sample data provide a convenient way to check the accuracy of your design. (2) The sample data help improve communications with users in discussing your design. (3) You can use the sample data to develop prototype applications and to test querie
The purpose of the several types of constraints (business rules) in the relational data model is to...	...facilitate maintaining the accuracy and integrity of data in the database.
The major types of integrity constraints are:	Domain constraints, entity integrity, referential integrity, and action assertions.
A _____ is the set of values that may be assigned to an attribute.	domain
A _____ usually consists of the following components: domain name, meaning, data type size, and allowable values or allowable range.	domain definition
The _____ rule is designed to ensure that every relation has a primary key, and that the data values for that primary key are all valid.	entity integrity
The _____ rule states the following: No primary key attribute (or component of a primary key attribute) may be null.	entity integrity
A _____ is a rule that maintains consistency among the rows of two relations.	referential integrity constraint
The _____ rule states that if there is a foreign key in one relation, either each foreign key value must match a primary key value in another relation, or the foreign key value must be null.	referential integrity constraint
To create table definitions for tables, the _____ statements from the SQL data definition language are used.	CREATE TABLE
A _____ contains minimal redundancy and allows users to insert, modify, and delete the rows in a table without errors or inconsistencies.	well-structured relation
A(n) _____ in an error or inconsistency that may result when a user attempt to update a table that contains redundant data.	anomaly
The three types of anomalies are:	(1) Insertion anomaly (2) Deletion anomaly (3) Modification anomaly
The three reasons in the process of transforming E-R diagrams to relations are:	(1) CASE tools often cannot model more complex data relationships (2) There are sometimes legitimate alternatives where you will need to choose a particular solution. (3) Be prepared to perform a quality check on the results obtained with a CASE tool.
Step 1 in transforming E-R diagrams to relations is...	Map Regular Entities
Step 2 in transforming E-R diagrams to relations is...	Map Weak Entities
Step 3 in transforming E-R diagrams to relations is...	Map Binary Relationships
Step 4 in transforming E-R diagrams to relations is...	Map Associative Entities
Step 5 in transforming E-R diagrams to relations is...	Map Unary Relationships
Step 6 in transforming E-R diagrams to relations is...	Map Ternary (and n-ary) Relationships
Step 7 in transforming E-R diagrams to relations is...	Map Supertype/Subtype Relationships
A nonkey attribute is also called a _____.	descriptor
A _____ is a serial number or other system assigned primary key for a relation.	surrogate primary key
A surrogate key should be created when any of the following conditions hold:	(1) There is a composite primary key (2) The natural primary key is inefficient (3) The natural primary key is recycled
A _____ is a foreign key in a relation that references the primary key values of that same relation.	recursive foreign key
_____ is a formal process for deciding which attributes should be grouped together in a relation so that all anomalies are removed.	Normalization
There are three major occasions during the overall database development process when you can usually benefit from using normalization...	(1) During conceptual data modeling (2) During logical database design (3) Reverse-engineering older systems
Four main goals of normalization are:	(1) Minimize data redundancy (2) Simplify the enforcement of referential integrity constraints (3) Make it easier to maintain data (4) Provide a better design that is an improved representation of the real world and a stronger basis for future growth
A _____ is a state of a relation that results from applying simple rules regarding functional dependencies to that relation.	normal form
There are six kinds of normal form:	(1) First normal form (2) Second normal form (3) Third normal form (4) Boyce-Codd normal form (5) Fourth normal form (6) Fifth normal form
First normal form is...	...any multivalued attributes have been removed, so there is a single value at the intersection of each row and column of the table.
Second normal form is...	...any partial functional dependencies have been removed.
Third normal form is...	...any transitive dependencies have been removed.
Boyce-Codd normal form is...	...any remaining anomalies that result from functional dependencies have been removed.
Fourth normal form is...	...any multivalued dependencies have been removed.
Fifth normal form is...	...any remaining anomalies have been removed.
A _____ is a constraint between two attributes or two sets of attributes.	functional dependency
The attribute on the left side of the arrow in a functional dependency is called a _____.	determinant
A _____ is an attribute, or combination of attributes, that uniquely identifies a row in a relation.	candidate key
A candidate key must satisfy two properties:	(1) Unique identification (2) Nonredundancy
A relation is in _____ if the following two constraints both apply: (1)there are no repeating groups in the relation & (2)a primary key has been defined, which uniquely identifies each row in the relation.	first normal form (1NF)
Manipulating the data in the table can lead to anomalies such as the following:	(1) Insertion anomaly (2) Deletion anomaly (3) Update anomaly
A relation is in _____ if it is in first normal form and contains no partial dependencies.	second normal form (2NF)
A _____ exists when a nonkey attribute is functionally dependent on part (but not all) of the primary key.	partial functional dependency
A relation is in _____ if it is in second normal form and no transitive dependencies exist.	third normal form (3NF)
A _____ in a relation is a functional dependency between two (or more) nonkey attributes.	transitive dependency
_____ are two (or more) attributes having different names but the same meaning, as when they describe the same characteristic of an entity.	synonyms
A(n) _____ is an alternative name used for an attribute.	alias
An attribute that may have more than one meaning is called a _____.	homonym
A(n) _____ is a primary key whose value is unique across all relations.	enterprise key

Which attribute can uniquely identify a row in a table?

SQL keys are used to uniquely identify rows in a table. SQL keys can either be a single column or a group of columns. Super key is a single key or a group of multiple keys that can uniquely identify tuples in a table.

What is an attribute or group of attributes that uniquely identify a tuple in a relation?

In the relational data model a superkey is a set of attributes that uniquely identifies each tuple of a relation. Because superkey values are unique, tuples with the same superkey value must also have the same non-key attribute values.

Which attribute of a row is called as?

A row, or record, is also known as a tuple. The columns in a table is a field and is also referred to as an attribute. You can also think of it this way: an attribute is used to define the record and a record contains a set of attributes.

Which of the following can be used to uniquely identify a row?

Primary key is the minimal set of attributes.

Is an attribute or a combination of attributes that uniquely identifies each row in a relation?

Chapter5(LogicalDatabaseDesignAndTheRelationalModel)

Which attribute can uniquely identify a row in a table?

What is an attribute or group of attributes that uniquely identify a tuple in a relation?

Which attribute of a row is called as?

Which of the following can be used to uniquely identify a row?

zusammenhängende Posts

What type of constraints in Supertype that an attribute of the supertype whose values determine the target subtype s )?

Which of the following constraints ensures that the foreign key value in the referencing relation must exist in the primary key attribute of the referenced relation?

Which of the following security attribute is compromised when data information is changed or tampered?

Which of the following access control methods is based on permissions defined by a role such as manager authorized user or guest )?

Werbung

NEUESTEN NACHRICHTEN

Which incentive plans are specifically designed to promote group performance

According to the flsa, which individual is most likely a nonexempt employee?

Reactive and protective behaviors designed to avoid action, blame, or change are termed ________.

The machiavellian personality is characterized by the will to manipulate and the desire for power.

Ist ein mann in brunn gefallen noten

Which of the following biometric authentication systems is the most accepted by users?

Was ist der Unterschied zwischen Hanf und CBD?

Wie viele noten braucht man für eine zeugnisnote sachsen-anhalt

Wie fühlt man sich wenn man schwanger ist am anfang

Kann man Basaltemperatur auch tagsüber Messen?

Werbung

Populer

Werbung

Um

Legal

Hilfe

Sozial