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2. Projection (relational algebra) - Wikipedia

   en.wikipedia.org/.../Projection_(relational_algebra)

   In practical terms, if a relation is thought of as a table, then projection can be thought of as picking a subset of its columns. For example, if the attributes are (name, age), then projection of the relation {(Alice, 5), (Bob, 8)} onto attribute list (age) yields {5,8} – we have discarded the names, and only know what ages are present.

3. Selection (relational algebra) - Wikipedia

   en.wikipedia.org/wiki/Selection_(relational_algebra)

   Mutation and Selection. In relational algebra, a selection (sometimes called a restriction in reference to E.F. Codd's 1970 paper [1] and not, contrary to a popular belief, to avoid confusion with SQL's use of SELECT, since Codd's article predates the existence of SQL) is a unary operation that denotes a subset of a relation.

4. Relational algebra - Wikipedia

   en.wikipedia.org/wiki/Relational_algebra

   The relational algebra uses set union, set difference, and Cartesian product from set theory, and adds additional constraints to these operators to create new ones.. For set union and set difference, the two relations involved must be union-compatible—that is, the two relations must have the same set of attributes.

5. Projection (set theory) - Wikipedia

   en.wikipedia.org/wiki/Projection_(set_theory)

   Projection (measure theory) Projection (linear algebra) – Idempotent linear transformation from a vector space to itself; Projection (relational algebra) – Operation that restricts a relation to a specified set of attributes; Relation (mathematics) – Relationship between two sets, defined by a set of ordered pairs

6. Kelly Clarkson Seemingly Shades Ex-Husband Brandon ... - AOL

   www.aol.com/lifestyle/kelly-clarkson-seemingly...

   Kelly Clarkson isn’t visiting any ghosts of Christmas past this holiday season.. On Thursday, Dec. 19, the Grammy winner, 42, appeared to throw shade at her ex-husband Brandon Blackstock in a ...

7. Category:Relational algebra - Wikipedia

   en.wikipedia.org/wiki/Category:Relational_algebra

   Projection (relational algebra) R. ... Selection (relational algebra) String operations This page was last edited on 24 December 2022, at 00:30 (UTC) ...