Database Design Methodology Chapter 2

Step 2.1 is to derive relations for the logical data model.

It is validated using normalization.

Integrity constraints ensure that the logical data model accurately represents important rules and conditions of the data.

<p>The relations are validated against user transactions to ensure they support user requirements.</p> Signup and view all the answers

<p>In Step 2.5, the logical data model is reviewed with the users for validation.</p> Signup and view all the answers

<p>Step 2.6 is the optional step to merge logical data models into a global data model.</p> Signup and view all the answers

<p>Future growth should be assessed to ensure the model can accommodate future data requirements.</p> Signup and view all the answers

<p>Step 2.6 is omitted if the database only has a single user view or uses a centralized approach.</p> Signup and view all the answers

<p>A foreign key acts as a reference to a primary key in another relation, establishing a link between the two entities.</p> Signup and view all the answers

<p>The parent entity is identified as the entity that posts its primary key into the child entity as a foreign key.</p> Signup and view all the answers

<p>A strong entity type has its own unique primary key and does not rely on any other entity for its identification.</p> Signup and view all the answers

<p>A weak entity type cannot be uniquely identified by its attributes alone and requires a foreign key from a strong entity.</p> Signup and view all the answers

<p>In a one-to-many relationship, a single instance of the parent entity can be associated with multiple instances of the child entity.</p> Signup and view all the answers

<p>A multi-valued attribute can hold multiple values for a single entity, unlike simple attributes which can hold only one.</p> Signup and view all the answers

<p>A superclass/subclass relationship establishes a hierarchy where the subclass inherits attributes from the superclass while having its unique attributes.</p> Signup and view all the answers

<p>Composite attributes are broken down into their constituent simple attributes when creating relations for strong entities.</p> Signup and view all the answers

<p>It means that not every client specifies preferences, leading the Client entity to be the parent and the Preference entity to be the child.</p> Signup and view all the answers

<p>Because the foreign key attribute from the Client relation is essential for uniquely identifying records in the Preference relation.</p> Signup and view all the answers

<p>The designation is arbitrary unless additional information clarifies the relationship.</p> Signup and view all the answers

<p>Any new primary keys or candidate keys should be identified and the data dictionary should be updated accordingly.</p> Signup and view all the answers

<p>The designation is arbitrary when there is no additional information to guide the decision on which entity is parent or child.</p> Signup and view all the answers

<p>This implies that while many cars are utilized by staff, not all staff members use cars, indicating a one-to-many dynamic within the relationship.</p> Signup and view all the answers

<p>The data dictionary serves as a reference to maintain the accuracy and integrity of the database after identifying new keys.</p> Signup and view all the answers

<p>The database should allow for clients to exist without corresponding entries in the Preference relation.</p> Signup and view all the answers

<p>To ensure that relationships between tables are maintained correctly and to prevent orphaned records.</p> Signup and view all the answers

<p>Global relation diagram.</p> Signup and view all the answers

<p>To ensure that the database meets user needs and to prevent future issues in data management.</p> Signup and view all the answers

<p>The documentation.</p> Signup and view all the answers

<p>A global ER diagram is based on local ER diagrams, while a global relation diagram focuses on merged relations.</p> Signup and view all the answers

<p>Out-of-date documentation.</p> Signup and view all the answers

<p>They uniquely identify records within a table, ensuring data integrity.</p> Signup and view all the answers

<p>Update the documentation simultaneously with the model changes.</p> Signup and view all the answers

<p>Merging relationships and foreign keys ensures consistency and integrity across data models, allowing for a unified global model.</p> Signup and view all the answers

<p>Foreign keys with the same name and purpose can be directly merged into the global model, simplifying the data structure.</p> Signup and view all the answers

<p>In the StaffClient views, the Registers relationship models a staff member registering a client, while in the Branch views, it involves registering a client at a specific branch.</p> Signup and view all the answers

<p>Multiplicity constraints help identify conflicts in relationships, ensuring that merged elements accurately reflect the intended data interactions.</p> Signup and view all the answers

<p>Resolving conflicts ensures that the merged data accurately represents all user views without any discrepancies or loss of information.</p> Signup and view all the answers

<p>The Registers relationship from the StaffClient user views is ignored in favor of equivalent relationships from the Branch user views.</p> Signup and view all the answers

<p>These relationships can be merged by analyzing their functionalities and aligning them under a common naming convention.</p> Signup and view all the answers

<p>Ignoring conflicting relationships allows for a more streamlined model, eliminating redundancy and potential errors.</p> Signup and view all the answers

<p>The primary goal is to ensure the relations created support the required transactions and to validate through normalization.</p> Signup and view all the answers

<p>Only the areas of the model that resulted in changes during the merging process should be checked.</p> Signup and view all the answers

<p>It is necessary to ensure that the model accurately represents the data requirements of the enterprise as perceived by users.</p> Signup and view all the answers

<p>The distinction between local logical data models and the global logical data model is no longer necessary.</p> Signup and view all the answers

<p>The assessment includes determining significant changes likely in the foreseeable future and whether the model can accommodate them.</p> Signup and view all the answers

<p>It involves evaluating the logical data model's capability to be extended for future developments.</p> Signup and view all the answers

<p>Normalization ensures that the relations created are structured to reduce redundancy and improve data integrity.</p> Signup and view all the answers

<p>Documentation describing the model should accompany it during the review.</p> Signup and view all the answers