What is the difference in the writing of these two types of database query statements?

loryiori

When uploading pictures to the database in binary, I use sql = insert into DD (dd) values ​​('"+ dd +"') "; it cannot be displayed, but I replaced it with sql = insert into DD (dd) values ​​(@dd); It can be displayed normally.
Does the former not support binary uploads? Or any other reason?

o01029

Never tried this, help you

q21692451

The latter uses stored procedures

loryiori

The latter is not a stored procedure, but just a parameter.

saintfrosty

This is an asp.net forum originally, it is not convenient to discuss in-depth database issues. Your question has something to do with ado.net, just answer it briefly:

Your first way, assuming the syntax is correct, then the compiler first converts the variable bb to a string (using the object's ToString method), and then combines the string into a sql variable. You can set a breakpoint to see what the result of the sql variable is, and see if the command sent to the database is what you mean by submitting binary image data.

In the first way, SQL is not the correct logical meaning at all.

The second method is very standard, and it is clear that ado.net's SQL command parameters are designed in this way, there is nothing to say.

loryiori

The variable bb here is of type byte [].
What I want to make sure is: assuming everything is OK, can I upload binary data in the first way?

loryiori

top!

crazypig14

Maybe it's a relationship

zhengminglin

The first way is to upload binary data. It is not possible. I have used C # to write binary numbers to the database. It must be defined as a binary type. And it cannot be added.

caokongpigq

1. insert into DD (dd) values ​​(""+dd+" ")" is wrong, I am dizzy,,, is a single quote
insert into DD (dd) values ​​("'+dd+"')";
2. The @ in sql=insert into DD (dd) values ​​(@dd) automatically adds single quotes. This is the function of @,
@ Can also be expressed by address, @C:\asdfa.exe is equal to c:\\asdfa.exe