Is a null in sql(language) equivalent to a NULL in c++

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Is a null in sql equivalent to a null in C++.I need to write this app where I have to check frequently to know if a field in a record is null.I just needed to know if the two are equivalent so I can determine how best to check for nullity.

Posted 4-Feb-14 0:25am

Gbenbam

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CPallini · Accepted Answer · 2014-02-04T00:33:00

Solution 1

They are NOT equivalent. I guess the C# Nullable types[^] are more closer to SQL corrispondent types.

Posted 4-Feb-14 0:33am

CPallini

Andrius Leonavicius · Accepted Answer · 2014-02-04T01:06:00

Solution 2

Hi,

NULL in SQL and C++ are not equivalent. In SQL, NULL indicates that the value is unknown (data value does not exist in the database) and is different from an empty or zero value. Here is more information (SQL Server):
Null Values[^]

Posted 4-Feb-14 1:06am

Andrius Leonavicius

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Gbenbam 4-Feb-14 7:33am

So how on earth does one test for a null in a C++ program that queries database using sql?

markkuk 4-Feb-14 9:51am

See the documentation of your database interface library. It should provide a function to test for SQL NULL values, e.g. MySQL C++ connector has ResultSet::IsNull()

Andrius Leonavicius 4-Feb-14 16:16pm

markkuk is right. Unfortunately, there is no general answer how to test for a NULL and it depends on particular C++ library for accessing SQL database. Good luck.

Is a null in sql(language) equivalent to a NULL in c++

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Is a null in sql(language) equivalent to a NULL in c++

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