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Questions and Answers
What is the primary goal of normalization in database design?
What is the primary goal of normalization in database design?
- To increase data redundancy for faster data retrieval.
- To complicate data maintenance for better data security.
- To provide a complex design that obscures the real world.
- To minimize data redundancy and avoid anomalies. (correct)
Which of the following is the most accurate definition of normalization in databases?
Which of the following is the most accurate definition of normalization in databases?
- A tool used for backing up and restoring database files.
- A technique for encrypting sensitive data within a database for security.
- A method of quickly inserting large amounts of data into a database.
- A process of organizing data to minimize redundancy and improve data integrity. (correct)
What does normalization primarily aim to prevent when managing relational databases?
What does normalization primarily aim to prevent when managing relational databases?
- Unauthorized access.
- Data redundancy and anomalies. (correct)
- System crashes.
- Network congestion.
Which of the following scenarios is most likely to occur in a database that has NOT been properly normalized?
Which of the following scenarios is most likely to occur in a database that has NOT been properly normalized?
What is the main purpose of decomposing relations into smaller, well-structured relations during normalization?
What is the main purpose of decomposing relations into smaller, well-structured relations during normalization?
Which statement accurately describes a key benefit of database normalization?
Which statement accurately describes a key benefit of database normalization?
What term describes the problems that arise in database tables that have not been normalized?
What term describes the problems that arise in database tables that have not been normalized?
In a database context, what typically results from modification anomalies?
In a database context, what typically results from modification anomalies?
Which anomaly occurs when you cannot insert a new record into a table because of a missing attribute?
Which anomaly occurs when you cannot insert a new record into a table because of a missing attribute?
Which type of anomaly occurs when deleting a record inadvertently removes other unrelated information?
Which type of anomaly occurs when deleting a record inadvertently removes other unrelated information?
What type of data anomaly arises when an update to a single piece of data requires changes to multiple records, and some are missed?
What type of data anomaly arises when an update to a single piece of data requires changes to multiple records, and some are missed?
Breaking an existing unnormalized table into two or more smaller tables aims to resolve which common database problem?
Breaking an existing unnormalized table into two or more smaller tables aims to resolve which common database problem?
What does functional dependency describe in the context of database normalization?
What does functional dependency describe in the context of database normalization?
In database normalization, what is indicated when knowing the value of one attribute is sufficient to determine the value of another attribute?
In database normalization, what is indicated when knowing the value of one attribute is sufficient to determine the value of another attribute?
In database design, what term best describes a non-key attribute that depends on only part of the primary key?
In database design, what term best describes a non-key attribute that depends on only part of the primary key?
What normalization issue arises when a non-key attribute is functionally dependent on only a portion of the primary key?
What normalization issue arises when a non-key attribute is functionally dependent on only a portion of the primary key?
In database normalization, what is the term for a functional dependency between the primary key and a non-key attribute that is dependent on the primary key via another non-key attribute?
In database normalization, what is the term for a functional dependency between the primary key and a non-key attribute that is dependent on the primary key via another non-key attribute?
Which of the following dependencies is characterized by a non-key attribute depending on another non-key attribute, which in turn depends on the primary key?
Which of the following dependencies is characterized by a non-key attribute depending on another non-key attribute, which in turn depends on the primary key?
What is the first normal form (1NF) primarily concerned with?
What is the first normal form (1NF) primarily concerned with?
Which type of attribute does the First Normal Form (1NF) specifically aim to eliminate?
Which type of attribute does the First Normal Form (1NF) specifically aim to eliminate?
What is the primary goal of Second Normal Form (2NF) in database normalization?
What is the primary goal of Second Normal Form (2NF) in database normalization?
What step must be taken to achieve Second Normal Form (2NF) if a table is already in First Normal Form (1NF)?
What step must be taken to achieve Second Normal Form (2NF) if a table is already in First Normal Form (1NF)?
What type of dependency does Third Normal Form (3NF) primarily address by removing?
What type of dependency does Third Normal Form (3NF) primarily address by removing?
What specific condition does a table need to satisfy to be in Third Normal Form (3NF)?
What specific condition does a table need to satisfy to be in Third Normal Form (3NF)?
What characteristic defines a table that is in First Normal Form (1NF)?
What characteristic defines a table that is in First Normal Form (1NF)?
A table is in Second Normal Form. What condition does this imply about its structure?
A table is in Second Normal Form. What condition does this imply about its structure?
A database is in Third Normal Form. What characteristics describe its dependencies?
A database is in Third Normal Form. What characteristics describe its dependencies?
In a properly normalized database, what does the term 'atomic' refer to regarding attribute values?
In a properly normalized database, what does the term 'atomic' refer to regarding attribute values?
A company stores customer data including multiple phone numbers in a single field. Which normal form is this table violating?
A company stores customer data including multiple phone numbers in a single field. Which normal form is this table violating?
In a table, CustomerID determines CustomerName and CustomerAddress. CustomerAddress is thus transitively dependent on CustomerID if it is determined by what?
In a table, CustomerID determines CustomerName and CustomerAddress. CustomerAddress is thus transitively dependent on CustomerID if it is determined by what?
In a database table with columns for OrderID, ProductID, ProductName, and ProductPrice, which normal form is violated if ProductName and ProductPrice depend only on ProductID?
In a database table with columns for OrderID, ProductID, ProductName, and ProductPrice, which normal form is violated if ProductName and ProductPrice depend only on ProductID?
For a table in 2NF, what must be addressed to bring the table to 3NF?
For a table in 2NF, what must be addressed to bring the table to 3NF?
A table includes EmployeeID, DepartmentID, and DepartmentName. If DepartmentName depends on DepartmentID, which normal form is violated?
A table includes EmployeeID, DepartmentID, and DepartmentName. If DepartmentName depends on DepartmentID, which normal form is violated?
In a database, the table OrderT(OrderID, OrderDate, CustomerID) represents order information. The table Customer(CustomerID, CustomerName, CustomerAddress) holds customer details. Which dependency is exemplified?
In a database, the table OrderT(OrderID, OrderDate, CustomerID) represents order information. The table Customer(CustomerID, CustomerName, CustomerAddress) holds customer details. Which dependency is exemplified?
Consider a database design with OrderT, Product, Order_Detail, and Customer tables. Which dependency isn't specifically addressed by achieving Third Normal Form?
Consider a database design with OrderT, Product, Order_Detail, and Customer tables. Which dependency isn't specifically addressed by achieving Third Normal Form?
A database table has the structure ORDERPRODUCT(orderid, orderdate, custid, custname, custadrs, {prodid, proddesc, prodfin, uprice, qty}). What normal form is this table in?
A database table has the structure ORDERPRODUCT(orderid, orderdate, custid, custname, custadrs, {prodid, proddesc, prodfin, uprice, qty}). What normal form is this table in?
Flashcards
Normalization
Normalization
A process of analyzing a relation to ensure that it is well-formed.
Normalization involves
Normalization involves
Breaking down relations to produce smaller, well-structured relations.
Normalization is
Normalization is
Deciding which attributes should be grouped together in a relation.
Normalized Relation
Normalized Relation
Rows can be inserted, deleted, or modified without creating anomalies.
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Normalization Goal: Minimize?
Normalization Goal: Minimize?
Conserving space and avoiding anomalies.
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Normalization Goal: Provide a
Normalization Goal: Provide a
Ensuring the design is an improved representation of the real world.
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Normalization is a
Normalization is a
Used to ensure data are well structured from an organization-wide view.
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Modification Anomalies
Modification Anomalies
Tables that are not normalized are susceptible to modification anomalies.
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Insertion Anomaly
Insertion Anomaly
Occurs when certain attributes cannot be inserted into the database without other attributes.
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Update Anomaly
Update Anomaly
Exists when one or more instances of duplicated data are not fully updated.
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Deletion Anomaly
Deletion Anomaly
Occurs when certain attributes are lost because of the deletion of other attributes.
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Functional dependency
Functional dependency
Knowing the value of one attribute is enough to tell you the value of another attribute in the same table.
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Partial functional dependency
Partial functional dependency
When a non-key attribute is functionally dependent on part (but not all) of the primary key.
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Transitive dependency
Transitive dependency
A functional dependency between the primary key and one or more nonkey attributes via another nonkey attribute
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First Normal Form
First Normal Form
Multivalued attribute have been removed.
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Second Normal Form
Second Normal Form
Any partial functional dependencies have been removed.
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Third Normal Form
Third Normal Form
Any transitive dependencies have been removed.
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Normalization Definitions
- Normalization is analyzing a relation to ensure that it is well formed.
- Normalization decomposes relations into smaller, well-structured relations.
- Normalization is a formal process that decides how attributes should be grouped to remove anomalies.
- A normalized relation allows rows to be inserted, deleted, or modified without creating anomalies.
Normalization Goals
- Minimize data redundancy, conserve space and avoid anomalies.
- Easier data maintenance.
- Provide a better DB design.
- Represent the real world more accurately.
Normalization as a Technique
- Normalization is a logical data-modeling technique.
- It ensures well-structured data across an organization.
Modification Anomalies
- Modification anomalies occur in unnormalized tables.
- Insertion Anomaly happens when certain attributes cannot be inserted without the presence of other attributes.
- Update Anomaly happens when one or more instances of duplicated data are updated, but not all.
- Deletion Anomaly happens when certain attributes are lost due to other attributes' deletion.
Solving Modification Problems
- Most modification issues are solved by breaking a table into two or more tables via normalization.
Functional Dependency
- Functional dependency exists when the value of an attribute or set of attributes can determine the value of another attribute within the same table.
- Example: SSS No. determines Employee’s Name and Employee’s contributions.
- Example: Bank Account No. determines Customer Name and Amount of Deposit.
Partial Functional Dependency
- Partial functional dependency present when a non-key attribute depends on part, but not all, of the primary key.
Transitive Dependency
- Transitive dependency arises when there is a functional dependency between the primary key and one or more non-key attributes through another non-key attribute.
- If A is PK, B and C are non-key attributes, C depends on B, and B depends on A, then C is transitively dependent on A.
- Example: DeptID is the primary key, MgrID and MgrName are non-key attributes; MgrName depends on MgrID, and MgrID depends on DeptID, then MgrName is transitively dependent on DeptID.
Steps in Normalization
- Normalization occurs in stages, each corresponding to a normal form.
- First Normal Form (1NF): Multi-valued attributes (repeating groups) are removed.
- Second Normal Form (2NF): Partial functional dependencies are removed
- Third Normal Form (3NF): Transitive dependencies are removed.
Tables with Multi-Valued Attributes
- Tables with Multi-Valued Attributes - Not in 1st Normal Form
- Tables with No Multi-Valued Attributes - In 1st Normal Form
Functional Dependencies: Order ID, Product ID, Customer ID
- Order_ID -> Order_Date, Customer_ID, Customer_Name, Customer_Address
- Product_ID -> Product_Description, Product_Finish, Unit_Price
- Order_ID, Product_ID -> Order_Quantity
- Customer_ID -> Customer_Name, Customer_Address
Normal Forms
- 1NF PLUS No partial dependencies = Second Normal Form
- 2NF PLUS No transitive dependencies = Third Normal Form
Tables and Attributes
- OrderT(orderID, orderdate,custid)
- Product(prodid, proddesc,finish, uprice)
- Order_detail(orderID, prodid, qty)
- Customer(custid,custname,custadrs)
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