null from C# getting converted into 'NULL' in Sql Server

Question

I am trying to insert NULL value in Sql Server if I have null value in corresponding C# String object like below :

String Residence = xmlDoc.Descendants("Appointment").Single().Element("StateOfResidence") == null ? null : xmlDoc.Descendants("Appointment").Elements("StateOfResidence").Single().Value;

I am using Entity framework for Database access. So if Residence is null, 'NULL' gets inserted into Database instead of NULL. How can insert NULL for null ?

Pretty sure that `NULL` and `null` are the same thing. Are you seeing `NULL` in SSMS? — Tim, Jun 04 '14 at 09:15
`xmlDoc.Descendants("Appointment").Elements("StateOfResidence").Single().Value` <- check is this returning a string `"NULL"`, if yes then you may need to change your logic — sallushan, Jun 04 '14 at 09:18

score 1 · Answer 1 · edited Jun 04 '14 at 09:22

1

A databases null value is of a different type to the regular null values that you use in C#. So to insert a null value into a database you must use the below code type, instead of null or "NULL"

DBNull.Value

edited Jun 04 '14 at 09:22

Amicable

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answered Jun 04 '14 at 09:16

Dhaval Patel

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score 1 · Accepted Answer · answered Jun 04 '14 at 10:43

Entity Framework should handle this for you, so the issue you have is that

xmlDoc.Descendants("Appointment").Single().Element("StateOfResidence")

actually has the string value "NULL"

you could change your logic to say that

String Residence = xmlDoc.Descendants("Appointment").Single().Element("StateOfResidence");
if(Residence == "NULL")
{
    Residence = null;
}

but that's a bit hacky really - I'd personally be looking at why the xml you have actually has the string value "NULL" in what presumably should be empty nodes if the xml is under your control.

null from C# getting converted into 'NULL' in Sql Server

2 Answers2