Data deletion: Delete

--Data deletion: Do I need to ask if I need to delete it when I delete it? At the same time after the project, delete is often not really deleted, but instead do delete the tag
--Syntax:
--delete from table name where condition

Delete from Teacher
--delete the specified person information
Delete from Teacher where id=26
--Use Delete to remove the features:
--1. It is a strip of records to be deleted. Each deletion requires that the operation be logged to the log file, and the efficiency is not high.
--2. It does not allow the identity column to be recalculated from the identity seed, but to continue the identity column of the last record before

--truncate table name-no conditions
--1. Delete all records of a table at once, without paying attention to the number of records, log file minimized write mode, more efficient
--2. The identity column is recalculated from the identity seed
TRUNCATE TABLE teacher

Data deletion: Delete