Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
484 views
in Technique[技术] by (71.8m points)

sql server - What does a timestamp in T-Sql mean in C#?

I'm trying to develop a model object to hold a Sql Server row, and I understand perfectly how to do this except for the T-Sql/SqlServer timestamp. The table is defined as:

CREATE TABLE activity (
activity_id int
, ip_address varchar(39)
, user_id varchar(255)
, message_text
, dt timestamp
)

When I resolve a table row to my object, for an int or a string I would expect to do something like:

ActivityID = (int)dataReader["activity_id"];
IPAddress = (string)dataReader["ip_address"];

But what do I do about the timestamp column? There's no "timestamp" datatype that I can find anywhere. I know that Sql Server stores timestamp as an 8 byte binary, but what is this normally the equivalent of in .NET?

Edited to add: A little extra information... this is a row being returned from a DB2 table on our mainframe coming through a Sql Server view. "Rowversion" isn't an option, and DB2 is handing the column off as a timestamp. If timestamp and rowversion are identical, maybe I can treat it as one, but otherwise I'm stuck with timestamp.

Edited again to add: This project is going to drive me nuts. It will, at least, be a short trip. Anyway, yes @JoelC this is a Sql Server view into a DB2 database on the mainframe. I was finally able to track down one of our DBAs, who explained disdainfully that "of course" a DB2 TIMESTAMP comes across as to a Sql Server view as a datetime. From his tone of voice I guess only noobs don't know this. That's why he named it "datetime" in the actual view, Duh! (I gave it a different name in my example so as to not trigger commentary on naming conventions -- the actual data model diagram says it's a TIMESTAMP and names it timestamp). So, in this event, apparently one must cast it to a DateTime. I think I may begin considering becoming a DBA so that I, too, can drive programmers crazy. Sorry if I misled any of the responders to this question -- it was unintentional, as I was actually expecting a timestamp to be, well, a timestamp. Silly me. Thanks are especially due to Microsoft for naming a byte-array datatype a "timestamp" when it has nothing to do with dates and times. I haven't the vaguest idea which response to mark as the Answer. Sigh.

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

According to this post

you'll have to cast it to a byte array.

byte[] dt = dataReader["dt"] as byte[];

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...