The database is a way to store the data in tabular form. The database is a collection of the tables and all the tables are connected with the keys. The keys are the column their respective data has uniquely differentiated the rows. The main types of keys are the primary key, foreign ...
The Optimizer can determine this based on UNIQUE and PRIMARY KEY constraints on the tables. When outer joins are used the row preserving table (table without the outer join operator) must come after the other table in the predicate (table with the outer join operator) to ensure all of...
Data is accessed by looking up key values in an index and returning rowids. A rowid uniquely identifies an individual row in a particular data block. This block is read via single block i/o. In this example an index is used to find the relevant row(s) and then the table is accessed ...
A database table must have a primary key and may also have foreign keys. When a database is normalized the data will appear only once in one table and will not be duplicated in another table.Answer and Explanation: Become a member and unlock all...