Untitled Quiz

Questions and Answers

Selects all tuples that satisfy the selection condition from a relation R. (correct)

Selects all tuples from a database.

Selects tuples based on a specific attribute.

Selects unique tuples from a relation.

Selects tuples that match certain criteria.

Finds the difference between two relations.

Produces a new relation with only some attributes of R and removes duplicate tuples. (correct)

Combines two relations based on a condition.

All combinations of tuples from R_1 and R_2 that satisfy the join condition. (correct)

A relation with no duplicate tuples.

Only those tuples where a specific attribute matches.

A relation that combines attributes from multiple relations.

Produces combinations of tuples using only equality comparisons. Signup and view all the answers

Natural Join does not include the join attributes of R_2 in the resulting relation. Signup and view all the answers

Produces a relation including all tuples in R_1 or R_2, or both. Signup and view all the answers

Including all tuples in both R_1 and R_2. Signup and view all the answers

All tuples from R_1 that are not in R_2. Signup and view all the answers

Relations with attributes of R_1 and R_2 and includes all possible combinations of tuples. Signup and view all the answers

To produce a relation R(X) that includes all tuples t[X] in R_1(Z) that appear in R_1 with every tuple from R_2(Y). Signup and view all the answers

Study Notes

Select: Filters tuples from relation R based on a specified condition, retaining only those that meet the criteria.
Project: Creates a new relation containing specific attributes from relation R while eliminating duplicate tuples.
Theta Join: Generates all possible pairs of tuples from relations R_1 and R_2 that fulfill a designated join condition.
Equijoin: Similar to theta join, but only includes pairs of tuples from R_1 and R_2 based on equality comparisons in the join condition.
Natural Join: A special type of equijoin that automatically combines tuples from R_1 and R_2 while excluding duplicate join attributes. Duplicate attribute names do not need specification.
Union: Combines tuples from R_1 and R_2, including all unique tuples from both. Relations R_1 and R_2 must be compatible in terms of attributes for this operation.
Intersection: Results in a relation containing only tuples that appear in both R_1 and R_2. Both relations must be union compatible.
Difference: Produces a relation containing tuples from R_1 that are absent in R_2. This operation requires R_1 and R_2 to be union compatible.
Cartesian Product: Forms a new relation by merging attributes from R_1 and R_2, resulting in all possible combinations of their tuples.
Division: Creates relation R(X) consisting of all tuples t[X] from R_1(Z) that are associated with every tuple in R_2(Y), where Z is the union of X and Y.