Re: Using a Database
- Posted by ronaustin at alltel.net
Oct 13, 2003
--------------Boundary-00=_FNZPQL80000000000000
charset="iso-8859-1"
=0D
=0D
-------Original Message-------=0D
=0D
From: EUforum at topica.com=0D
Subject: Re: Using a Database=0D
=0D
=0D
=0D
ronaustin at alltel.net wrote:=0D
> I need to write out a file that has a six byte key (an account =0D
> number) and a 500 byte record. The first two fields in the record =0D
> contain the last name and the first name of a person. I need to be able=
=0D
> to recall the person's record either by the account number or the first=
=0D
> and last name. =0D
=0D
EDS only supports one key (in your case the account number).=0D
You could search all the records for a matching first and last name.=0D
For a few thousand names that would take a fraction of a second.=0D
You might want to do a kind of "fuzzy" match on the name, since=0D
people don't always provide their names in exactly the same way=0D
each time.=0D
=0D
For greater speed, you could also set up a secondary index=0D
fairly easily, but you would have to maintain it yourself.=0D
You would create a second table with {first name, last name}=0D
as the key. The data would be a sequence of account numbers=0D
of people with that name. EDS would then do a fast binary search=0D
to find a name. The corresponding account number(s) could then=0D
be looked up in the main table using a fast binary search.=0D
You'd have to update this table whenever you added or=0D
deleted an account from the main table.=0D
=0D
> There can be several people on a network adding new=0D
> records and updating existing records. It might be possible that two =0D
> people try to change the same record at the same time. The system I am =
=0D
> currently using has recording locking to keep this from happening. I =0D
> understand the EDS database has file locking which I assume would only =
=0D
> allow one person to read and write while the other six or seven compute=
r =0D
> operators drank coffee.=0D
> =0D
> 1. Am I correct in assuming that this is the way the EDS database works=
?=0D
=0D
Yes, it currently has only file locking. For many applications that's=0D
all you need. i.e. if the process that is writing the database=0D
only needs access for a few seconds or less at a time.=0D
The other processes can poll until the database is free.=0D
One good thing about EDS, especially on the Web, is that=0D
it is very lightweight - a database can be opened, read or written,=0D
and closed very quickly.=0D
=0D
> 2. If so, is it going to be changed. When?=0D
=0D
Probably some day.=0D
There hasn't been a huge demand for it yet.=0D
=0D
> 3. If not, how does it work?=0D
> =0D
> 4. Should I skip the EDS and use MySQL with a ODBC wrapper?=0D
=0D
Matthew Lewis could probably answer that.=0D
=0D
Regards,=0D
Rob Craig=0D
Rapid Deployment Software=0D
http://www.RapidEuphoria.com=0D
=0D
Thanks for the info. Typically someone would pull up a record and then
verify the information was correct before writing it back out. Then ther=
e
might be further delays because they had to answer the phone, etc., so I
couldn't use a file lock. In the past I have built my own locking table
which worked ok and I have also used multiple indexes which I had to
maintain.=0D
=0D
I think I will start with EDS and then change to SQL if I have to. Many =
of
the files I will be using are look-up files that will work okay without
being locked.=0D
=0D
=0D
=0D
=0D
TOPICA - Start your own email discussion group. FREE!=0D
=0D
=0D
=0D
=0D
=2E=20
--------------Boundary-00=_FNZPQL80000000000000
Content-Type: Text/HTML;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3Diso-8859-=
1">
<META content=3D"IncrediMail 1.0" name=3DGENERATOR>
<!--IncrdiXMLRemarkStart>
<IncrdiX-Info>
<X-FID>FLAVOR00-NONE-0000-0000-000000000000</X-FID>
<X-FVER></X-FVER>
<X-CNT>;</X-CNT>
</IncrdiX-Info>
<IncrdiXMLRemarkEnd-->
</HEAD>
<BODY style=3D"BACKGROUND-POSITION: 0px 0px; FONT-SIZE: 12pt; MARGIN: 5px=
10px 10px; FONT-FAMILY: Arial" bgColor=3D#ffffff background=3D"" scroll=3D=
yes ORGYPOS=3D"0" X-FVER=3D"3.0">
<TABLE id=3DINCREDIMAINTABLE cellSpacing=3D0 cellPadding=3D2 width=3D"100=
%" border=3D0>
<TBODY>
<TR>
<TD id=3DINCREDITEXTREGION style=3D"FONT-SIZE: 12pt; CURSOR: auto; FONT-F=
AMILY: Arial" width=3D"100%">
<DIV><BR> </DIV>
<DIV id=3DIncrediOriginalMessage><I>-------Original Message-------</I></D=
IV>
<DIV> </DIV>
<DIV id=3Dreceivestrings>
<DIV dir=3Dltr style=3D"FONT-SIZE: 11pt" <i><B>From:</B></I> <A href=3D"m=
ailto:EUforum at topica.com">EUforum at topica.com</A></DIV>
<DIV dir=3Dltr style=3D"FONT-SIZE: 11pt" <i><B>Date:</B></I> Monday, Octo=
ber 13, 2003 7:28:12 PM</DIV>
<DIV dir=3Dltr style=3D"FONT-SIZE: 11pt" <i><B>To:</B></I> <A href=3D"mai=
lto:EUforum at topica.com">EUforum</A></DIV>
<DIV dir=3Dltr style=3D"FONT-SIZE: 11pt" <i><B>Subject:</B></I> Re: Using=
a Database</DIV></DIV>
<DIV> </DIV>
<DIV>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D The Euphoria Mailing List =3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D <BR><BR><BR><A href=3D"mailto:ronaustin@al=
ltel.net">ronaustin at alltel.net</A> wrote:<BR>> I need to write out a f=
ile that has a six byte key (an account <BR>> number) and a 500 byte r=
ecord. The first two fields in the record <BR>> contain the last name =
and the first name of a person. I need to be able <BR>> to recall the =
person's record either by the account number or the first <BR>> and la=
st name. <BR><BR>EDS only supports one key (in your case the account numb=
er).<BR>You could search all the records for a matching first and last na=
me.<BR>For a few thousand names that would take a fraction of a second.<B=
R>You might want to do a kind of "fuzzy" match on the name, since<BR>peop=
le don't always provide their names in exactly the same way<BR>each time.=
<BR><BR>For greater speed, you could also set up a secondary index<BR>fai=
rly easily, but you would have to maintain it yourself.<BR>You would crea=
te a second table with {first name, last name}<BR>as the key. The data wo=
uld be a sequence of account numbers<BR>of people with that name. EDS wou=
ld then do a fast binary search<BR>to find a name. The corresponding acco=
unt number(s) could then<BR>be looked up in the main table using a fast b=
inary search.<BR>You'd have to update this table whenever you added or<BR=
>deleted an account from the main table.<BR><BR>> There can be several=
people on a network adding new<BR>> records and updating existing rec=
ords. It might be possible that two <BR>> people try to change the sam=
e record at the same time. The system I am <BR>> currently using has r=
ecording locking to keep this from happening. I <BR>> understand the E=
DS database has file locking which I assume would only <BR>> allow one=
person to read and write while the other six or seven computer <BR>> =
operators drank coffee.<BR>> <BR>> 1. Am I correct in assuming that=
this is the way the EDS database works?<BR><BR>Yes, it currently has onl=
y file locking. For many applications that's<BR>all you need. i.e. if the=
process that is writing the database<BR>only needs access for a few seco=
nds or less at a time.<BR>The other processes can poll until the database=
is free.<BR>One good thing about EDS, especially on the Web, is that<BR>=
it is very lightweight - a database can be opened, read or written,<BR>an=
d closed very quickly.<BR><BR>> 2. If so, is it going to be changed. W=
hen?<BR><BR>Probably some day.<BR>There hasn't been a huge demand for it =
yet.<BR><BR>> 3. If not, how does it work?<BR>> <BR>> 4. Should =
I skip the EDS and use MySQL with a ODBC wrapper?<BR><BR>Matthew Lewis co=
uld probably answer that.<BR><BR>Regards,<BR>Rob Craig<BR>Rapid Deploymen=
t Software<BR><A href=3D"http://www.RapidEuphoria.com">http://www.RapidEu=
phoria.com</A></DIV>
<DIV> </DIV>
<DIV><STRONG><FONT color=3D#ff8000>Thanks for the info. Typically s=
omeone would pull up a record and then verify the information was correct=
before writing it back out. Then there might be further delays bec=
ause they had to answer the phone, etc., so I couldn't use a file lock. &=
nbsp; In the past I have built my own locking table which worked ok and I=
have also used multiple indexes which I had to maintain.</FONT></STRONG>=
</DIV>
<DIV><STRONG><FONT color=3D#ff8000></FONT></STRONG> </DIV>
<DIV><STRONG><FONT color=3D#ff8000>I think I will start with EDS and then=
change to SQL if I have to. Many of the files I will be using are =
look-up files that will work okay without being locked.</FONT></STRONG></=
DIV>
<DIV><BR><BR>--^---------------------------------------------------------=
-------<BR>This email was sent to: <A href=3D"mailto:ronaustin at alltel.net=
">ronaustin at alltel.net</A><BR><BR>EASY UNSUBSCRIBE click here: <A href=3D=
"http://topica.com/u/?b1dd66.b6KEgr.cm9uYXVz">http://topica.com/u/?b1dd66=
=2Eb6KEgr.cm9uYXVz</A><BR>Or send an email to: <A href=3D"mailto:EUforum-=
unsubscribe at topica.com">EUforum-unsubscribe at topica.com</A><BR><BR>TOPICA =
- Start your own email discussion group. FREE!<BR><A href=3D"http://www.t=
opica.com/partner/tag02/create/index2.html">http://www.topica.com/partner=
/tag02/create/index2.html</A><BR>--^-------------------------------------=
---------------------------<BR><BR><BR><BR><BR>. </DIV></TD></TR>
<TR>
<TD id=3DINCREDIFOOTER width=3D"100%">
<TABLE cellSpacing=3D0 cellPadding=3D0 width=3D"100%">
<TBODY>
<TR>
<TD width=3D"100%"></TD>
<TD id=3DINCREDISOUND vAlign=3Dbottom align=3Dmiddle></TD>
<TD id=3DINCREDIANIM vAlign=3Dbottom align=3Dmiddle></TD></TR></TBODY></T=
--------------Boundary-00=_FNZPQL80000000000000--
|
Not Categorized, Please Help
|
|
