Ans: The main Idea for the Sampling Algorithm is to select a small sample , one that fits in main memory of the database of transaction view more..

Ans: Aggregate functions view more..

Ans: Null values present special problems in relational operations, including arithmetic operations, comparison operations, and set operations. view more..

Ans: The main idea of Sampling Algorithm is to select a small sample , one that fits in main memory , of the database of transaction view more..

Ans: SQL provides a mechanism for nesting subqueries. A subquery is a select-from where expression that is nested within another query. view more..

Ans: SQL provides a mechanism for nesting subqueries. A subquery is a select-from where expression that is nested within another query. view more..

Ans: We have restricted our attention until now to the extraction of information from the database. Now, we show how to add,remove, or change information with SQL. view more..

Ans: We introduced the natural join operation. SQL provides other forms of the join operation, including the ability to specify an explicit join predicate, and the ability to include in the result tuples that are excluded by natural join. We shall discuss these forms of join in this section. view more..

Ans: In our examples up to this point, we have operated at the logical-model level. That is, we have assumed that the relations in the collection we are given are the actual relations stored in the database. view more..

Ans: A transaction consists of a sequence of query and/or update statements. view more..

Ans: Integrity constraints ensure that changes made to the database by authorized users do not result in a loss of data consistency. view more..