15.00 - SQL and Indexes - Teradata Database

Teradata Database Design

prodname
Teradata Database
vrm_release
15.00
category
User Guide
featnum
B035-1094-015K

SQL and Indexes

Basic I/O Required by SQL DML Requests

The five basic SQL data manipulation language statements, SELECT, INSERT, DELETE, UPDATE, and MERGE, can all use available indexing and partitioning to access and manipulate table rows. Alternatively, the Optimizer applies a full‑table scan if that is more efficient or if there is no applicable index for the request.

The following table summarizes the I/O types required by these four statements.

 

Statement

Types of I/O Required

SELECT

Read

INSERT

Read and Write

DELETE

UPDATE

MERGE