SQL Archives - Shoumadip Das

Category: SQL

As of Oracle 12.1, you can now define invisible columns in relational tables. An invisible column is a user-defined hidden…

• Simple CASE statement evaluates a expression and executes the statement or sequence of statements associated with the first condition…

The SELECT FOR UPDATE statement is a special variation of the normal SELECT statement, which proactively issues row locks on…

Traditionally, performing a function on an indexed column in the where clause of a query guaranteed an index would not…

Reverse B-TREE key indexes reverses the bytes of the key value in the index to reduce Index block contention. Index…

BITMAP index are different from B-TREE index in the manner they store data. • B-TREE index stores data in tree…

The “ON PREBUILT TABLE” clause is used when you have already created a replicated table using “CTAS” and now want…

A join view is a view based on a join. Special considerations apply when you issue a DML(INSERT, UPDATE, or…

The SYS_CONTEXT function is used in both SQL & PL/SQL to return information about the Oracle environment that you’re working…

External tables are read-only tables that allow Oracle to query data that is stored outside the database in flat files….