理解range-predicatepivoted partitioning in Database

A predicate is a condition expression that evaluates to a boolean value, either true or false.

Predicates can be used as follows:

• In a SELECT statement’s WHERE clause or HAVING clause to determine which rows are relevant to a particular query.
• In a JOIN operation’s ON clause to determine which rows are relevant to the join operation
• In an UPDATE or DELETE statement’s WHERE clause, to detemine which rows are to be modified
• In a WHERE CURRENT OF statement’s AND clause
• In a CREATE TRIGGER statement’s WHEN clause to determine when to apply triggered action code

A partition is a division of a logical database or its constituent elements into distinct independent parts.

It is popular in disributed database management systems, where each partition may be spread over multiple nodes, with users at the node performing local transactions on the partition.

Current high-end RDMS provides for different criteria to split the database. They take a partitioning key and assign a partition based on certain criteria:

A pivot table is a table of statistics that summarizes the data of a more extensive table.

This summary might include sums, averages, or other statistics, which the pivot table groups together in a meaningful way.

Pivoting data is a rather common problem that comes in many different flavors. At its heart, the requirement is to transpose data from multiple rows into columns of a single row.