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I was trying to retrieve data from SQL Server via ADO in C++ and how can I check the Null Values the recordset fields? thre is no IsNUll() function?
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The DBNull class represents a nonexistent value. In a database, for example, a column in a row of a table might not contain any data whatsoever. That is, the column is considered to not exist at all instead of merely not having a value. A DBNull object represents the nonexistent column.
By using the assignment operator (“=”), you can set any value of a column to NULL by using the Update Statement.
IsNullOrEmpty() Method of C# This method is used when you want to check whether the given string is Empty or have a null value or not? If any string is not assigned any value, then it will have Null value. The symbol of assigning Null value is “ “or String. Empty(A constant for empty strings).
Testing for DBNull in a C++ ADO record set involves checking the fieldpointer->Value property, which is of type VARIANT. To test for null variant values, you check the vt field, which for null values is VT_NULL.
So to test for DBNull, check fieldpointer->Value.vt == VT_NULL
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