A table with three columns is given below. For each relational operation given in the 1st column find the best matches from 2nd and 3rd columns.
Operation |
Symbol |
Feature |
1. Select |
(a) ∩ |
(i) Output will be only those rows in the first operand table that are not in the second operand |
2. Union |
(b) -(minus) |
(ii) Gives the horizontal subset of the operand table. |
3. Set Difference |
(c) σ(sigma)
(d) ∪ |
(iii) Gives a table that contains all rows of the operand tables.
(iv) Gives the vertical subset of the operand table. |