D427 - Data Management complete
questions with detailed verified accurate
answers
A table has a name, a fixed tuple of columns, and varying sets of rows.
A column has a name and a data type.
A row is a unnamed set of values. Each corresponds to a column and belongs to the columns
data type.
A data type is a name set of values, from which column values are drawn. - answer ✔✔-
Relational data structure
DATABASES MATHEMATICS FILES
table relation file
column attribute field
row tuple record
data type domain data type - answer ✔✔-Similar concepts in databases
A query selects a specific row by specifying one or more row values. Ex:
SELECT EmployeeName FROM Employee WHERE EmployeeID = 2594; - answer ✔✔-Can a query
select one specific row from a table?
,What is the result of a relational operation? - answer ✔✔-What is the result of a relational
operation?
Select, Project, Product, Join, Union, Intersect, Difference, Rename, Aggregate - answer ✔✔-
Name some operational operations
FALSE
- Most SQL queries implement several operations. Ex: SELECT Name FROM Employee WHERE
Salary > 50000; implements both a select and a project operation. - answer ✔✔-An SQL
statement can implement only one relational operation. T/F
All relational tables should have a column with a primary key.
primary keys identify individual rows. - answer ✔✔-Unique primary key is an example of a
relational rule.
T/F
FALSE
-Delete cascade is a business rule, not a relational rule. The delete cascade rule requires that,
when a row of a particular table is deleted, all related rows are also deleted. Deleting related
rows depends on business policy, and may apply to some tables but not others. - answer ✔✔-
Delete cascade is an example of a relational rule.
T/F
True
, -Depending on how tables are specified, some relational rules can be violated. Ex: A table with
no primary key can be created. However, rule violations often create business problems and
should normally be avoided or automatically prevented. - answer ✔✔-Data in a relational
database can violate relational rules.
T/F
Relational rule - answer ✔✔-All tables must have a primary key with no repeated values.
R or B rule
Business rule - answer ✔✔-All rows in a particular column must have known values.
R or B rule
Relational rule - answer ✔✔-Different columns of the same table must have different names. R
or B rule
True
-Designers use SQL to create the database and tables
-The users uses SQL to insert, retrieve, update, and delete from the tables. - answer ✔✔-A
database designer and database user both use SQL.
T/F
FALSE
- SQL implementations differs in small ways between databases. - answer ✔✔-All database
systems use identical SQL statements
T/F
questions with detailed verified accurate
answers
A table has a name, a fixed tuple of columns, and varying sets of rows.
A column has a name and a data type.
A row is a unnamed set of values. Each corresponds to a column and belongs to the columns
data type.
A data type is a name set of values, from which column values are drawn. - answer ✔✔-
Relational data structure
DATABASES MATHEMATICS FILES
table relation file
column attribute field
row tuple record
data type domain data type - answer ✔✔-Similar concepts in databases
A query selects a specific row by specifying one or more row values. Ex:
SELECT EmployeeName FROM Employee WHERE EmployeeID = 2594; - answer ✔✔-Can a query
select one specific row from a table?
,What is the result of a relational operation? - answer ✔✔-What is the result of a relational
operation?
Select, Project, Product, Join, Union, Intersect, Difference, Rename, Aggregate - answer ✔✔-
Name some operational operations
FALSE
- Most SQL queries implement several operations. Ex: SELECT Name FROM Employee WHERE
Salary > 50000; implements both a select and a project operation. - answer ✔✔-An SQL
statement can implement only one relational operation. T/F
All relational tables should have a column with a primary key.
primary keys identify individual rows. - answer ✔✔-Unique primary key is an example of a
relational rule.
T/F
FALSE
-Delete cascade is a business rule, not a relational rule. The delete cascade rule requires that,
when a row of a particular table is deleted, all related rows are also deleted. Deleting related
rows depends on business policy, and may apply to some tables but not others. - answer ✔✔-
Delete cascade is an example of a relational rule.
T/F
True
, -Depending on how tables are specified, some relational rules can be violated. Ex: A table with
no primary key can be created. However, rule violations often create business problems and
should normally be avoided or automatically prevented. - answer ✔✔-Data in a relational
database can violate relational rules.
T/F
Relational rule - answer ✔✔-All tables must have a primary key with no repeated values.
R or B rule
Business rule - answer ✔✔-All rows in a particular column must have known values.
R or B rule
Relational rule - answer ✔✔-Different columns of the same table must have different names. R
or B rule
True
-Designers use SQL to create the database and tables
-The users uses SQL to insert, retrieve, update, and delete from the tables. - answer ✔✔-A
database designer and database user both use SQL.
T/F
FALSE
- SQL implementations differs in small ways between databases. - answer ✔✔-All database
systems use identical SQL statements
T/F
