NULL vs Empty String

Alan Gamboa <[email protected]> Thu, 15 Aug 2002 16:34:30 -0400
Newsgroups gmane.comp.windows.devel.oledb.devel
Message-ID <[email protected]>
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Hello all, a question on best practices...

Which is the accepted practice in database storage for varchar type
fields...

record is defined as below:

class CAccRecType
{
    public:
    CAccRecType() { Clear() };

    LONG     lKey;
    TCHAR    tcVal[10];
    int            iMoreData;

    void Clear() { memset(this,0,sizeof(*this) );
}

usage:

    CAccRecType    rec;
    rec.lKey = 100L;
    rec.iMoreData = 50;
    [ add record to database ]

if the field is not "used" in a record, what should be stored on the
database -  NULL or "an empty string" ?

tia

Alan Gamboa
CCG Systems, Inc.


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<BODY>
<DIV><FONT face=Arial size=2><SPAN class=834252220-15082002>Hello all, a
question&nbsp;on best practices...</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=834252220-15082002></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2><SPAN class=834252220-15082002>Which is the
accepted practice in database storage for varchar type
fields...</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=834252220-15082002></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2><SPAN class=834252220-15082002>record is defined as
below:</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=834252220-15082002></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2><SPAN class=834252220-15082002>class
CAccRecType</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=834252220-15082002>{</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=834252220-15082002>&nbsp;&nbsp;&nbsp;
public:</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=834252220-15082002>&nbsp;&nbsp;&nbsp;
CAccRecType() { Clear() };</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=834252220-15082002>&nbsp;&nbsp;&nbsp;
</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=834252220-15082002>&nbsp;&nbsp;&nbsp;
LONG&nbsp;&nbsp;&nbsp;&nbsp; lKey;</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=834252220-15082002>&nbsp;&nbsp;&nbsp;
TCHAR&nbsp;&nbsp;&nbsp; tcVal[10];</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=834252220-15082002>&nbsp;&nbsp;&nbsp;
int&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
iMoreData;</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=834252220-15082002>&nbsp;&nbsp;
</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=834252220-15082002>&nbsp;&nbsp;&nbsp;
void Clear() { memset(this,0,sizeof(*this) );</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=834252220-15082002>}</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=834252220-15082002></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2><SPAN
class=834252220-15082002>usage:</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=834252220-15082002></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2><SPAN class=834252220-15082002>&nbsp;&nbsp;&nbsp;
CAccRecType&nbsp;&nbsp;&nbsp; rec;</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=834252220-15082002>&nbsp;&nbsp;&nbsp;
rec.lKey = 100L;</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=834252220-15082002>&nbsp;&nbsp;&nbsp;
rec.iMoreData = 50;</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=834252220-15082002>&nbsp;&nbsp;&nbsp; [
add record to database ]</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=834252220-15082002></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2><SPAN class=834252220-15082002>if the field is not
"used" in a record, what should be stored on the database - &nbsp;NULL or "an
empty string" ?</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=834252220-15082002></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2><SPAN
class=834252220-15082002>tia</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=834252220-15082002></SPAN></FONT>&nbsp;</DIV>
<DIV align=left>
<DIV align=left><FONT face=Arial size=2>Alan Gamboa</FONT></DIV>
<DIV align=left><B><FONT face=Arial size=2>CCG Systems,
Inc.</FONT></B></DIV></DIV>
<DIV><FONT face=Arial size=2></FONT>&nbsp;</DIV></BODY></HTML>
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