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38. Referential ____ means that if the foreign key contains a value, that value refers to an existing valid tuple (row) in another relation. a. integrity c. direction b. uniqueness d. relations 39. To be considered minimally relational, the DBMS must support the key relational operators ____, PROJECT, and JOIN. 40. ____, also known as RESTRICT, yields values for all rows found in a table that satisfy a given condition. 41. ____ combines all rows from two tables, excluding duplicate rows. 42. A(n) ____ join links tables by selecting only the rows with common values in their common attribute(s). a. equal c. foreign b. unique d. natural 43. The ____ relational type is the “relational model ideal.”44. The set of possible values for an attribute is a ____. 45. The preferred placement for a foreign key when working with a 1:1 relationship is to ____. 46. The ____ type of attribute cannot be created in a DBMS. a. derived c. simple b. multivalued d. composite 47. A derived attribute ____.
48. When the PK of one entity does not contain the PK of a related entity, the relationship is ____. 49. The following step occurs first in the process of building an ERD: ____. 50. If the focus is on data-retrieval speed, you might also be forced to include ____ attributes in the design, which would not ordinarily be done. a. multivalued c. weak b. composite d. derived EXTRA CREDIT (worth up to 5 points, to a maximum exam score of 100%)A database user manual notes that, “The file contains two hundred records, each record containing nine fields.” Use appropriate relational database terminology to “translate” this statement.