Or rather, use database trigger carefully.
Trigger is convenient and easy to write, but wrong implementation of database trigger can cause serious performance issue.
Basic rule is to avoid database trigger at all cost, find alternative way to achieve same result. Below is a video from Pluralsight showing usage of a database trigger that performs poorly. The slow performance caused by overhead that comes with database trigger, in this case the operation reads more table that necessary. When alternative approach is used (setting default constraint on a column), the difference is significant.
Try it for yourself.
-- Create our demo CREATE TABLE [dbo].[charge_demo]( [charge_no] [dbo].[numeric_id] NOT NULL PRIMARY KEY CLUSTERED, [charge_no] [dbo].[numeric_id] NOT NULL, [provider_no] [dbo].[numeric_id] NOT NULL, [category_no] [dbo].[numeric_id] NOT NULL, [charge_dt] [datetime] NOT NULL, [charge_amt] [money] NOT NULL, [statement_no] [dbo].[numeric_id] NOT NULL, [charge_code] [dbo].[status_code] NOT NULL, [insert_dt] [datetime] NULL; GO -- Create our trigger CREATE TRIGGER [trg_i_charge_demo] ON [dbo].[charge_demo] AFTER INSERT AS BEGIN SET NOCOUNT ON; UPDATE [dbo].[charge_demo] SET [insert_dt] = GETDATE() FROM [dbo].[charge_demo] AS [c] INNERT JOIN inserted AS [i] ON [c].[charge_no] = [i].[charge_no]; END GO
Source: Hidden Side Effect of Trigger