<Tr> <Td> Update (Modify) </Td> <Td> UPDATE </Td> <Td> PUT / POST / PATCH </Td> <Td> PUT </Td> <Td> write </Td> </Tr> <Tr> <Td> Delete (Destroy) </Td> <Td> DELETE </Td> <Td> DELETE </Td> <Td> DELETE </Td> <Td> dispose </Td> </Tr> <P> The comparison of the database oriented CRUD operations to the HTTP methods has some flaws . Strictly speaking, both PUT and POST can create resources; the key difference is that POST leaves it up to the server to decide at what URI to make the new resource available, while PUT dictates what URI to use; URIs as a concept do not align neatly with CRUD . The significant point about PUT is that it will replace whatever resource the URI was previously referring to with a brand new version, hence the PUT method being listed for Update as well . PUT is a' replace' operation, which one could argue is not' update' . </P> <P> Although a relational database provides a common persistence layer in software applications, numerous other persistence layers exist . CRUD functionality can for example be implemented with object databases, XML databases, flat text files, or custom file formats . </P>

Describe basic insertion retrieval and updating statement in sql