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RE: Oracle and Record Locking

From: Shockey, David <DShockey_at_jwrinc.com>
Date: Thu, 27 Jul 2000 17:42:31 -0500
Message-Id: <10571.113184@fatcity.com>


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Database theorist call this concurrency control and Oracle's means is shared locking, meaning that only one transaction can have the data items selected for update (edit/delete) but other transactions can read the data items. Further, Oracle does not allow uncommitted changes to be read so the readers will see the data items in the same state that the updater begins with.

In theory interleaving transactions would be most efficient but there are many possible data integrity problems with interleaving.

Jared, is this pedantic? If so, will I be punished?

-----Original Message-----
From: Abdul Aleem [mailto:abchaudhary-ho_at_beaconhouse.edu.pk] Sent: Thursday, July 27, 2000 1:06 PM
To: Multiple recipients of list ORACLE-L Subject: RE: Oracle and Record Locking

Seth Dunehew

To my knowledge, FoxPro family of products also do that i.e., records fetched from the tables into a cursor have no relationship with the table. If same record is accessed by two different users, both have rights to update, the effective changes will be of the one who saves later.

In oracle, the moment a user initiates editing a record fetched into a form (developer 2000), it is marked as locked (automatically -for third party front-end / back-end this needs manual locking). The locks are automatically released, when the records are committed. I am talking about forms 4.5 and Oracle 8. Don't have any idea about earlier versions.

HTH! Aleem

 -----Original Message-----

Sent:	27 July 2000 20:18
To:	Multiple recipients of list ORACLE-L
Subject:	Oracle and Record Locking


We have a consultant at our shop who is convinced that Oracle is inadequate for a serious multi-user environment because of the lack of record locking and dynamic result sets. We have been using it to develop and deploy a OLTP system and haven't found any serious problems that could not be addressed.

The dynamic result set that he has mentioned has me a little puzzled. He is stating that relational databases that he has worked with in the past returned a result set to him for use in his apps that would change dynamically if another user changed one of the records that he was displaying. I'm a relative newcomer to the database arena, 2 years, but this is something new. I've been told by another developer that Access will do this, but he hadn't heard of any serious systems that do.

Has anyone else heard of databases that perform that function?

Any suggestions on resources related to record locking in Oracle? We have two other developers that have worked with it extensively in the past, but the consultant is convinced that he knows differently, so we do need some solid research to refute him.

Thanks

Seth Dunehew

-- 
Author: Seth Dunehew
  INET: sdunehew_at_medicalmatrix.com

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
San Diego, California        -- Public Internet access / Mailing Lists

-- 
Author: Abdul Aleem
  INET: abchaudhary-ho_at_beaconhouse.edu.pk

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
San Diego, California        -- Public Internet access / Mailing Lists
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<TITLE>RE: Oracle and Record Locking</TITLE>
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<P><FONT SIZE=3D2>Database theorist call this concurrency control and =
Oracle's means is shared locking, meaning that only one transaction can = have the data items selected for update (edit/delete) but other = transactions can read the data items.&nbsp; Further, Oracle does not = allow uncommitted changes to be read so the readers will see the data = items in the same state that the updater begins with.&nbsp; </FONT></P>
<P><FONT SIZE=3D2>In theory interleaving transactions would be most =
efficient but there are many possible data integrity problems with = interleaving.&nbsp; </FONT></P>
<P><FONT SIZE=3D2>Jared, is this pedantic?&nbsp; If so, will I be =
punished?</FONT>
</P>
<BR>

<P><FONT SIZE=3D2>-----Original Message-----</FONT>
<BR><FONT SIZE=3D2>From: Abdul Aleem [<A =
HREF=3D"mailto:abchaudhary-ho_at_beaconhouse.edu.pk">mailto:abchaudhary-ho@= beaconhouse.edu.pk</A>]</FONT>
<BR><FONT SIZE=3D2>Sent: Thursday, July 27, 2000 1:06 PM</FONT>
<BR><FONT SIZE=3D2>To: Multiple recipients of list ORACLE-L</FONT>
<BR><FONT SIZE=3D2>Subject: RE: Oracle and Record Locking</FONT>
</P>
<BR>

<P><FONT SIZE=3D2>Seth Dunehew</FONT>
</P>

<P><FONT SIZE=3D2>To my knowledge, FoxPro family of products also do =
that i.e., records</FONT>
<BR><FONT SIZE=3D2>fetched from the tables into a cursor have no =
relationship with the table.</FONT>
<BR><FONT SIZE=3D2>If same record is accessed by two different users, =
both have rights to</FONT>
<BR><FONT SIZE=3D2>update, the effective changes will be of the one who =
saves later.</FONT>
</P>

<P><FONT SIZE=3D2>In oracle, the moment a user initiates editing a =
record fetched into a form</FONT>
<BR><FONT SIZE=3D2>(developer 2000), it is marked as locked =
(automatically -for third party</FONT>
<BR><FONT SIZE=3D2>front-end / back-end this needs manual locking). The =
locks are automatically</FONT>
<BR><FONT SIZE=3D2>released, when the records are committed. I am =
talking about forms 4.5 and</FONT>
<BR><FONT SIZE=3D2>Oracle 8. Don't have any idea about earlier =
versions.</FONT>
</P>

<P><FONT SIZE=3D2>HTH!</FONT>
</P>

<P><FONT SIZE=3D2>Aleem</FONT>
</P>

<P><FONT SIZE=3D2>&nbsp;-----Original Message-----</FONT>
<BR><FONT SIZE=3D2>Sent:&nbsp;&nbsp; 27 July 2000 20:18</FONT>
<BR><FONT SIZE=3D2>To:&nbsp;&nbsp;&nbsp;&nbsp; Multiple recipients of =
list ORACLE-L</FONT>
<BR><FONT SIZE=3D2>Subject:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
Oracle and Record Locking</FONT>
</P>
<BR>

<P><FONT SIZE=3D2>We have a consultant at our shop who is convinced =
that Oracle is inadequate</FONT>
<BR><FONT SIZE=3D2>for a serious multi-user environment because of the =
lack of record locking</FONT>
<BR><FONT SIZE=3D2>and dynamic result sets.&nbsp; We have been using it =
to develop and deploy a OLTP</FONT>
<BR><FONT SIZE=3D2>system and haven't found any serious problems that =
could not be addressed.</FONT>
</P>

<P><FONT SIZE=3D2>The dynamic result set that he has mentioned has me a =
little puzzled.&nbsp; He is</FONT>
<BR><FONT SIZE=3D2>stating that relational databases that he has worked =
with in the past</FONT>
<BR><FONT SIZE=3D2>returned a result set to him for use in his apps =
that would change</FONT>
<BR><FONT SIZE=3D2>dynamically if another user changed one of the =
records that he was</FONT>
<BR><FONT SIZE=3D2>displaying.&nbsp; I'm a relative newcomer to the =
database arena, 2 years, but</FONT>
<BR><FONT SIZE=3D2>this is something new.&nbsp; I've been told by =
another developer that Access will</FONT>
<BR><FONT SIZE=3D2>do this, but he hadn't heard of any serious systems =
that do.&nbsp; </FONT>
</P>

<P><FONT SIZE=3D2>Has anyone else heard of databases that perform that =
function?&nbsp; </FONT>
</P>

<P><FONT SIZE=3D2>Any suggestions on resources related to record =
locking in Oracle?&nbsp; We have</FONT>
<BR><FONT SIZE=3D2>two other developers that have worked with it =
extensively in the past, but</FONT>
<BR><FONT SIZE=3D2>the consultant is convinced that he knows =
differently, so we do need some</FONT>
<BR><FONT SIZE=3D2>solid research to refute him.</FONT>
</P>

<P><FONT SIZE=3D2>Thanks</FONT>
</P>

<P><FONT SIZE=3D2>Seth Dunehew</FONT>
<BR><FONT SIZE=3D2>-- </FONT>
<BR><FONT SIZE=3D2>Author: Seth Dunehew</FONT>
<BR><FONT SIZE=3D2>&nbsp; INET: sdunehew_at_medicalmatrix.com</FONT>
</P>

<P><FONT SIZE=3D2>Fat City Network Services&nbsp;&nbsp;&nbsp; -- (858) =
538-5051&nbsp; FAX: (858) 538-5051</FONT>
<BR><FONT SIZE=3D2>San Diego, =
California&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; -- Public Internet = access / Mailing Lists</FONT>
</P>

<P><FONT SIZE=3D2>-- </FONT>
<BR><FONT SIZE=3D2>Author: Abdul Aleem</FONT>
<BR><FONT SIZE=3D2>&nbsp; INET: =
abchaudhary-ho_at_beaconhouse.edu.pk</FONT>
</P>

<P><FONT SIZE=3D2>Fat City Network Services&nbsp;&nbsp;&nbsp; -- (858) =
538-5051&nbsp; FAX: (858) 538-5051</FONT>
<BR><FONT SIZE=3D2>San Diego, =
California&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; -- Public Internet = access / Mailing Lists</FONT>
<BR><FONT =
SIZE=3D2>---------------------------------------------------------------= -----</FONT>
<BR><FONT SIZE=3D2>To REMOVE yourself from this mailing list, send an =
E-Mail message</FONT>
<BR><FONT SIZE=3D2>to: ListGuru_at_fatcity.com (note EXACT spelling of =
'ListGuru') and in</FONT>
<BR><FONT SIZE=3D2>the message BODY, include a line containing: UNSUB =
ORACLE-L</FONT>
<BR><FONT SIZE=3D2>(or the name of mailing list you want to be removed =
Received on Thu Jul 27 2000 - 17:42:31 CDT

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