Hello,
I'm interested to know whats the difference between a many to one
relationship and a one to many relationship. Presuming 2 tables A and B
A (1 to many) B relationship is different with B (many to 1) A relationship?
I've thought that they're the same but I was watching a BI webcast when they
say that the logical relationship cannot be reversed...
Can someone enlighten this?They are the same relationship, just viewed from opposite perspectives.
I guess by saying the logical relationship cannot be reversed they mean
that if you can get the "1" row from a particular "many" row that does
not imply that you can then get back to the original "many" row just
given that "1" row (because there are now many rows that match up with
that 1 row). Does that make sense? (That's just a guess at what they
were trying to explain (not having any idea what they were saying
exactly) - maybe you could ask the presenter directly what they meant
precisely.)
*mike hodgson*
http://sqlnerd.blogspot.com
Nestor wrote:
>Hello,
>I'm interested to know whats the difference between a many to one
>relationship and a one to many relationship. Presuming 2 tables A and B
>A (1 to many) B relationship is different with B (many to 1) A relationship
?
>I've thought that they're the same but I was watching a BI webcast when the
y
>say that the logical relationship cannot be reversed...
>Can someone enlighten this?
>
>
Showing posts with label presuming. Show all posts
Showing posts with label presuming. Show all posts
Tuesday, March 20, 2012
Question on Relationships
Hello,
I'm interested to know whats the difference between a many to one
relationship and a one to many relationship. Presuming 2 tables A and B
A (1 to many) B relationship is different with B (many to 1) A relationship?
I've thought that they're the same but I was watching a BI webcast when they
say that the logical relationship cannot be reversed...
Can someone enlighten this?This is a multi-part message in MIME format.
--090208010402090701010204
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
They are the same relationship, just viewed from opposite perspectives.
I guess by saying the logical relationship cannot be reversed they mean
that if you can get the "1" row from a particular "many" row that does
not imply that you can then get back to the original "many" row just
given that "1" row (because there are now many rows that match up with
that 1 row). Does that make sense? (That's just a guess at what they
were trying to explain (not having any idea what they were saying
exactly) - maybe you could ask the presenter directly what they meant
precisely.)
--
*mike hodgson*
http://sqlnerd.blogspot.com
Nestor wrote:
>Hello,
>I'm interested to know whats the difference between a many to one
>relationship and a one to many relationship. Presuming 2 tables A and B
>A (1 to many) B relationship is different with B (many to 1) A relationship?
>I've thought that they're the same but I was watching a BI webcast when they
>say that the logical relationship cannot be reversed...
>Can someone enlighten this?
>
>
--090208010402090701010204
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
<tt>They are the same relationship, just viewed from opposite
perspectives.<br>
<br>
I guess by saying the logical relationship cannot be reversed they mean
that if you can get the "1" row from a particular "many" row that does
not imply that you can then get back to the original "many" row just
given that "1" row (because there are now many rows that match up with
that 1 row). Does that make sense? (That's just a guess at what they
were trying to explain (not having any idea what they were saying
exactly) - maybe you could ask the presenter directly what they meant
precisely.)</tt><br>
<div class="moz-signature">
<title></title>
<meta http-equiv="Content-Type" content="text/html; ">
<p><span lang="en-au"><font face="Tahoma" size="2">--<br>
</font></span> <b><span lang="en-au"><font face="Tahoma" size="2">mike
hodgson</font></span></b><span lang="en-au"><br>
<font face="Tahoma" size="2"><a href="http://links.10026.com/?link=http://sqlnerd.blogspot.com</a></font></span>">http://sqlnerd.blogspot.com">http://sqlnerd.blogspot.com</a></font></span>
</p>
</div>
<br>
<br>
Nestor wrote:
<blockquote cite="mideSQkMooYGHA.4620@.TK2MSFTNGP04.phx.gbl" type="cite">
<pre wrap="">Hello,
I'm interested to know whats the difference between a many to one
relationship and a one to many relationship. Presuming 2 tables A and B
A (1 to many) B relationship is different with B (many to 1) A relationship?
I've thought that they're the same but I was watching a BI webcast when they
say that the logical relationship cannot be reversed...
Can someone enlighten this?
</pre>
</blockquote>
</body>
</html>
--090208010402090701010204--
I'm interested to know whats the difference between a many to one
relationship and a one to many relationship. Presuming 2 tables A and B
A (1 to many) B relationship is different with B (many to 1) A relationship?
I've thought that they're the same but I was watching a BI webcast when they
say that the logical relationship cannot be reversed...
Can someone enlighten this?This is a multi-part message in MIME format.
--090208010402090701010204
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
They are the same relationship, just viewed from opposite perspectives.
I guess by saying the logical relationship cannot be reversed they mean
that if you can get the "1" row from a particular "many" row that does
not imply that you can then get back to the original "many" row just
given that "1" row (because there are now many rows that match up with
that 1 row). Does that make sense? (That's just a guess at what they
were trying to explain (not having any idea what they were saying
exactly) - maybe you could ask the presenter directly what they meant
precisely.)
--
*mike hodgson*
http://sqlnerd.blogspot.com
Nestor wrote:
>Hello,
>I'm interested to know whats the difference between a many to one
>relationship and a one to many relationship. Presuming 2 tables A and B
>A (1 to many) B relationship is different with B (many to 1) A relationship?
>I've thought that they're the same but I was watching a BI webcast when they
>say that the logical relationship cannot be reversed...
>Can someone enlighten this?
>
>
--090208010402090701010204
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
<tt>They are the same relationship, just viewed from opposite
perspectives.<br>
<br>
I guess by saying the logical relationship cannot be reversed they mean
that if you can get the "1" row from a particular "many" row that does
not imply that you can then get back to the original "many" row just
given that "1" row (because there are now many rows that match up with
that 1 row). Does that make sense? (That's just a guess at what they
were trying to explain (not having any idea what they were saying
exactly) - maybe you could ask the presenter directly what they meant
precisely.)</tt><br>
<div class="moz-signature">
<title></title>
<meta http-equiv="Content-Type" content="text/html; ">
<p><span lang="en-au"><font face="Tahoma" size="2">--<br>
</font></span> <b><span lang="en-au"><font face="Tahoma" size="2">mike
hodgson</font></span></b><span lang="en-au"><br>
<font face="Tahoma" size="2"><a href="http://links.10026.com/?link=http://sqlnerd.blogspot.com</a></font></span>">http://sqlnerd.blogspot.com">http://sqlnerd.blogspot.com</a></font></span>
</p>
</div>
<br>
<br>
Nestor wrote:
<blockquote cite="mideSQkMooYGHA.4620@.TK2MSFTNGP04.phx.gbl" type="cite">
<pre wrap="">Hello,
I'm interested to know whats the difference between a many to one
relationship and a one to many relationship. Presuming 2 tables A and B
A (1 to many) B relationship is different with B (many to 1) A relationship?
I've thought that they're the same but I was watching a BI webcast when they
say that the logical relationship cannot be reversed...
Can someone enlighten this?
</pre>
</blockquote>
</body>
</html>
--090208010402090701010204--
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