It appears truncation error after inserting value

I am having problems (SQL Server 2019) with the last sentence. After inserting product called MEMORIA USB it appears the next error:

Msg 2628, Level 16, State 1, Procedure TR_ProductoInsertado, Line 4 [Batch Start Line 28]
String or binary data would be truncated in table 'inventario.dbo.historial', column 'usuario'. Truncated value: 'DESKTOP-NLVD399\unna'.
The statement has been terminated.

If I delete the trigger and I insert the value then it works fine

create table productos
(
id_Cod int identity primary key,
cod_prod varchar(4) not null,
nombre varchar(50)not null,
existencia int not null,
)
GO

Create table historial

(fecha date,
descripcion varchar(100), 
usuario varchar(20))
GO

create table ventas
(cod_prod varchar(4),
precio money,
cantidad int
)
GO

create trigger TR_ProductoInsertado
on productos for insert
as
insert into historial values(getdate(), 'registro insertado', system_user)
go

insert into productos values('A001','MEMORIA USB 32GB',175);

Can someone help me ?

thanks in advance

Solution 1:

Your usuario has space for 20 characters, but your system_user is longer than that.

Either increase the length of the column, or truncate the system_user value before inserting it.

create trigger TR_ProductoInsertado 
on productos 
for insert 
as 
    insert into historial (fecha, descripcion, usuario)
    values(getdate(), 'registro insertado', LEFT(system_user, 20));