Default column value of a table - C#

Hi

How can i get default value of a table column in C#?

Thanks
Shiju
LVL 14
Shiju SasidharanAssoc Project ManagerAsked:
Who is Participating?
 
philipjonathanConnect With a Mentor Commented:
Instinctively speaking, this should be accomplished by the data adapter's FillSchema(), but just realised that MSDN says that this method configures other DataColumn properties, but not DefaultValue. I've never tried it myself to see if this is really so.
But if you are using MySQL, you can query default value from information_schema.
0
 
ororioleCommented:
There is a property:
if col is a DataColumn
col.DefaultValue can be get or set.
0
 
Shiju SasidharanAssoc Project ManagerAuthor Commented:
for null value column its not retrieving
0
Free Tool: IP Lookup

Get more info about an IP address or domain name, such as organization, abuse contacts and geolocation.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

 
Shiju SasidharanAssoc Project ManagerAuthor Commented:
if the data table is a result of a select query it is not fetching the default value
0
 
ororioleCommented:
This DefaultValue has nothing to do with the results of a query. Rather, when you create a new row in a C# data table, this will be the default value of the column.

The value returned from a sql query is controled by sql, not C#.
0
 
Shiju SasidharanAssoc Project ManagerAuthor Commented:
Is there any other way to get default values of a table column?
0
 
nsangaCommented:
why don't you use a separate SQL to get default values.....
0
 
Bob LearnedCommented:
Do you mean something like this?

   DataSet1.Tables[0].Columns[0].DefaultValue
0
 
Shiju SasidharanAssoc Project ManagerAuthor Commented:

TheLearnedOne,
yes i tried like that but without data set.
When we fill datatable using a select statement it doesnt fetch default value.

philipjonathan,
Your idea seems good. i will adopt that if there is no other alternative

 
0
 
ororioleCommented:
shijusn:
I think you may be asking for something that is not readily available, at least in the way you seem to think. As I mentioned before "The value returned from a sql query is controled by sql, not C#" or rather, it is the values in the rows of the table. Whatever values are in a sql table, those are the values you are going to get.

To look at it another way, the "normal" default for a column in T-SQL is NULL, as long as the column accepts NULLs. you CAN put DEFAULT definitions on columns during a CREATE TABLE or ALTER TABLE statement in T-SQL. You didnt mention if you are using SQL Server, but lets run with that. Put simply, what that does is define a DEFAULT value that will be used during an INSERT statement, if no explict value is supplied. If no DEFAULT is defined, a NULL is inserted. IF the column does not accept NULLs in that case, you get an error during the INSERT statement.

So if you are doing a SELECT statement from C#, you may get a NULL, you may get a value that was inserted, or you may get the DEFAULT value that was inserted. You aren't going to know how it got there or what the DEFAULT was.

Finally, there is a way to find out what the default definitions ON THE SQL COLUMN are. A system table, sys.default_constraints, contains the DEFAULT definitions for the entire database. See this link for an example of how to query this table: http://msdn.microsoft.com/en-us/library/ms173758(SQL.100).aspx. If you want to try it, You will probably want to read up on the other links referenced to understand how DEFAULTS are used. This would be a good place to begin: http://msdn.microsoft.com/en-us/library/ms189909(SQL.100).aspx
0
 
Shiju SasidharanAssoc Project ManagerAuthor Commented:
Well i tried this
SELECT   COLUMN_NAME, COLUMN_DEFAULT FROM  INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = <TableName>
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.