Data Modeling Flashcards
7 cards from real 1Z0-006 practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Data Modeling flashcards as text
In an Entity-Relationship diagram, what does a double rectangle around an entity name signify?
Answer: A weak entity that depends on another entity for identification
A double rectangle denotes a weak entity, which cannot be uniquely identified by its own attributes alone and relies on a parent (owner) entity.
Which normal form eliminates partial dependencies on a composite primary key?
Answer: Second Normal Form (2NF)
2NF removes partial dependencies, ensuring every non-key attribute depends on the whole composite primary key, not just part of it.
A CUSTOMER can place zero or many ORDERS, and each ORDER must belong to exactly one CUSTOMER. How is this cardinality expressed?
Answer: One (CUSTOMER) to many (ORDER) with mandatory participation on ORDER side
This is a one-to-many relationship where ORDER has mandatory participation (must have a customer) and CUSTOMER has optional participation (may have no orders).
What is a surrogate key in relational database design?
Answer: A system-generated artificial key with no business meaning
A surrogate key is a system-generated (e.g., auto-increment) identifier with no inherent business meaning, used to uniquely identify rows.
In data modeling, what does 'domain' refer to?
Answer: The set of all valid values an attribute can hold
A domain defines the permissible set of values for an attribute, including data type, length, format, and constraints.
Which relationship type in an ERD is represented by a line with crow's-foot notation on both ends?
Answer: Many-to-many
Crow's-foot notation on both ends of a relationship line indicates a many-to-many relationship between the two entities.
What is the purpose of a junction (bridge) table in relational database design?
Answer: To resolve a many-to-many relationship into two one-to-many relationships
A junction table sits between two entities in a many-to-many relationship, holding foreign keys to both and converting the relationship into two one-to-many links.