Kunci kekalahan

What is a Weak Entity?

• An entity that can exist independently without any other entity.

• An entity that has a primary key of its own.

• An entity that depends on another entity for existence (e.g., Dependent depends on Employee).

• An entity that is always optional in a relationship.

What is a Foreign Key (FK)?

• A unique identifier for a record in a table.

• Links tables by referencing a PK in another table.

• A type of primary key that allows duplicates.

• A constraint that prevents null values in a table.

What is a One-to-One (1:1) relationship?

• A common relationship where one entity is associated with many entities.

• A rare relationship where one entity is associated with one other entity.

• A relationship where multiple entities are associated with multiple entities.

• A relationship that does not exist in database design.

What is an Inner Join in SQL?

• Returns all rows from both tables regardless of match.

• Returns matching rows from both tables.

• Returns all rows from the first table and matching rows from the second.

• Returns only unmatched rows from both tables.

What is Normalization?

• A method to increase data redundancy.

• Process of organizing data to reduce redundancy and anomalies.

• A technique for data encryption.

• A way to visualize data in graphs.

What is Entity Integrity?

• Every table must have a unique PK.

• Entity Integrity ensures that all records are unique.

• Entity Integrity refers to the relationships between tables.

• Entity Integrity is a method of data encryption.

What is a Right Join in SQL?

• Returns all rows from the left table and matching rows from the right.

• Returns all rows from both tables regardless of matches.

• Returns all rows from the right table and matching rows from the left.

• Returns only the rows that have matching values in both tables.

What are the three normal forms (NF) in Normalization?

• 1NF: Eliminate repeating groups, ensure atomic values; 2NF: Remove partial dependencies; 3NF: Remove transitive dependencies.

• 1NF: Ensure all values are unique; 2NF: Remove duplicate rows; 3NF: Ensure all columns are dependent on the primary key.

• 1NF: Group similar data; 2NF: Ensure data is in tables; 3NF: Remove all null values.

• 1NF: Ensure data is in a single table; 2NF: Remove all foreign keys; 3NF: Ensure all data is in a single row.

What is a Full Join in SQL?

• Returns all rows when there is a match in either table.

• Returns only the rows with matching values in both tables.

• Returns all rows from the left table and matched rows from the right table.

• Returns all rows from the right table and matched rows from the left table.

What is a Database?

• A structured collection of data (end-user data and metadata).

• A random assortment of files and documents.

• A type of software used for web browsing.

• A collection of unrelated information.