C170 - Data Management – Applications
Questions with 100% Verified Correct Answers
First Normal Form
- when all non-key columns depend on the primary key
- a table with a primary key is in first normal form
- a table with no duplicate rows is in first normal form
Second Normal Form
- when all non-key columns depend on the whole primary key
- cannot depend on part of a composite primary key
- a table with a simple primary key is automatically in second normal form
A table with a simple primary key must be in what normal form?
- second normal form or higher
Third Normal Form
- when all non-key columns depend on the key, the whole key, and nothing but the key
Violation of Third Normal Form
- a non-key column depends on a column that is not unique
Boyce-Codd Normal Form
- whenever column A depends on column B, then B is unique
- same as Third Normal Form, except "non-key" is removed
A table has:
- columns A, B, C, D
- candidate key (A, C, D)
,- primary key (A, C, D)
- dependency D → B (in addition to dependencies on candidate keys)
What is the normal form of the table?
- First Normal Form
- the table has one candidate key, which is also a primary key
- any table with a primary key is in FIRST nf
- the non-key column B does not depend on the whole primary key...so not in SECOND
normal form
A table has:
- columns A, B, C, D
- candidate keys (C, D) and A
- primary key (C, D)
- dependencies on (C, D) and A only
What is the normal form of the table?
- Boyce-Codd
- The table is in Boyce-Codd normal form since all dependencies are on candidate keys.
- Therefore, all dependencies are on unique columns.
A table has:
- columns A, B, C, D
- candidate key (A, B, D)
- primary key (A, B, D)
- dependency C → D (in addition to dependencies on candidate keys)
, What is the normal form of the table?
- THIRD
- The table is in third normal form since non-key columns depend only on unique columns.
- D is not a non-key column.
- The table is not in Boyce-Codd normal form since D depends on the non-unique column C.
- Primary keys must be minimal, so no column in a composite primary key can be unique.
- Therefore, C is not unique.
A table has:
- columns A, B, C, D
- candidate keys D and (A, C)
- primary key (A, C)
- dependency B → C (in addition to dependencies on candidate keys)
What is the normal form of the table?
- THIRD
- The table is in third normal form since non-key columns depend only on unique columns.
- C is not a non-key column.
- The table is not in Boyce-Codd normal form since C depends on the non-unique column B.
- Primary keys must be minimal, so no column in a composite primary key can be unique.
- Therefore, B is not unique.
CREATE TABLE Employee (
ID SMALLINT UNSIGNED,
Name VARCHAR(60),
Questions with 100% Verified Correct Answers
First Normal Form
- when all non-key columns depend on the primary key
- a table with a primary key is in first normal form
- a table with no duplicate rows is in first normal form
Second Normal Form
- when all non-key columns depend on the whole primary key
- cannot depend on part of a composite primary key
- a table with a simple primary key is automatically in second normal form
A table with a simple primary key must be in what normal form?
- second normal form or higher
Third Normal Form
- when all non-key columns depend on the key, the whole key, and nothing but the key
Violation of Third Normal Form
- a non-key column depends on a column that is not unique
Boyce-Codd Normal Form
- whenever column A depends on column B, then B is unique
- same as Third Normal Form, except "non-key" is removed
A table has:
- columns A, B, C, D
- candidate key (A, C, D)
,- primary key (A, C, D)
- dependency D → B (in addition to dependencies on candidate keys)
What is the normal form of the table?
- First Normal Form
- the table has one candidate key, which is also a primary key
- any table with a primary key is in FIRST nf
- the non-key column B does not depend on the whole primary key...so not in SECOND
normal form
A table has:
- columns A, B, C, D
- candidate keys (C, D) and A
- primary key (C, D)
- dependencies on (C, D) and A only
What is the normal form of the table?
- Boyce-Codd
- The table is in Boyce-Codd normal form since all dependencies are on candidate keys.
- Therefore, all dependencies are on unique columns.
A table has:
- columns A, B, C, D
- candidate key (A, B, D)
- primary key (A, B, D)
- dependency C → D (in addition to dependencies on candidate keys)
, What is the normal form of the table?
- THIRD
- The table is in third normal form since non-key columns depend only on unique columns.
- D is not a non-key column.
- The table is not in Boyce-Codd normal form since D depends on the non-unique column C.
- Primary keys must be minimal, so no column in a composite primary key can be unique.
- Therefore, C is not unique.
A table has:
- columns A, B, C, D
- candidate keys D and (A, C)
- primary key (A, C)
- dependency B → C (in addition to dependencies on candidate keys)
What is the normal form of the table?
- THIRD
- The table is in third normal form since non-key columns depend only on unique columns.
- C is not a non-key column.
- The table is not in Boyce-Codd normal form since C depends on the non-unique column B.
- Primary keys must be minimal, so no column in a composite primary key can be unique.
- Therefore, B is not unique.
CREATE TABLE Employee (
ID SMALLINT UNSIGNED,
Name VARCHAR(60),
