If a row does not exists insert else don't insert in postgres [duplicate]

If a row does not exists insert else don't insert in postgres [duplicate]

References

Reference NO 1

http://stackoverflow.com/questions/15204621/if-a-row-does-not-exists-insert-else-dont-insert-in-postgres

Reference NO 2

http://stackoverflow.com/questions/4069718/postgres-insert-if-does-not-exist-already

Reference NO 3

http://stackoverflow.com/questions/11135501/postgresql-update-if-row-with-some-unique-value-exists-else-insert

Reference NO 4

http://stackoverflow.com/questions/7471625/fastest-check-if-row-exists-in-postgresql

Reference NO 5

http://www.postgresql.org/docs/8.1/static/rules-update.html

Reference NO 6

http://grokbase.com/t/postgresql/pgsql-general/1195ry58p8/conditional-insert

Reference NO 7

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Reference NO 8

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