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#1
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"free" ip number when I remove device from database?
Access 2007. Problem is when I delete the device (which has foreign
key, ipID) from device table the IP number from IP table (has ID, primary key) also deletes (relation 1:1). I want to "free" ip number when I remove device from database so IP number is not deleted and can be used later. How to accomplish this? Form looks for "free" addresses as follows: SELECT tblIP.ID, [ip] & "." & [ip2] & "." & [ip3] & "." & [ip4] AS [IP- number], tblDevice.ipID FROM tblIP LEFT JOIN tblDevice ON tblIP.ID = tblDevice.ipID ORDER BY tblIP.ip, tblIP.ip2, tblIP.ip3, tblIP.ip4 WHERE (((tblDevice.ipID) Is Null)); |
#2
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"free" ip number when I remove device from database?
Sandroid wrote:
Access 2007. Problem is when I delete the device (which has foreign key, ipID) from device table the IP number from IP table (has ID, primary key) also deletes (relation 1:1). I want to "free" ip number when I remove device from database so IP number is not deleted and can be used later. How to accomplish this? Form looks for "free" addresses as follows: SELECT tblIP.ID, [ip] & "." & [ip2] & "." & [ip3] & "." & [ip4] AS [IP- number], tblDevice.ipID FROM tblIP LEFT JOIN tblDevice ON tblIP.ID = tblDevice.ipID ORDER BY tblIP.ip, tblIP.ip2, tblIP.ip3, tblIP.ip4 WHERE (((tblDevice.ipID) Is Null)); Why are you deleting from tblIP at all? The usual way to do this is to either update the IP field(s) of the Device table, or delete the device entirely. In my opinion, this is definitely a case where you would want to store the separate octets *and* the full IP address so you can index and join on it. Then all the hard parts of this just plain go away. Or I suppose you could create an expression like you did in a plain select query (no joins) and then use that in a Find Unmatched query wizard... -- Message posted via http://www.accessmonster.com |
#3
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"free" ip number when I remove device from database?
Sandroid wrote:
Access 2007. Problem is when I delete the device (which has foreign key, ipID) from device table the IP number from IP table (has ID, primary key) also deletes (relation 1:1). I want to "free" ip number when I remove device from database so IP number is not deleted and can be used later. How to accomplish this? I must be forgetting how to read... or not awake yet. Do you have cascading deletes turned on between the two tables? If so, turn it off. -- Message posted via http://www.accessmonster.com |
#4
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"free" ip number when I remove device from database?
On 11 touko, 15:00, "PieterLinden via AccessMonster.com" u49887@uwe
wrote: Sandroid wrote: Access 2007. Problem is when I delete the device (which has foreign key, ipID) from device table the IP number from IP table (has ID, primary key) also deletes (relation 1:1). *I want to "free" ip number when I remove device from database so IP number is not deleted and can be used later. How to accomplish this? I must be forgetting how to read... or not awake yet. *Do you have cascading deletes turned on between the two tables? *If so, turn it off. -- Message posted viahttp://www.accessmonster.com cascading turned off - no help referential integrity turned off - no help which way to create the relation from IP to Device or vice versa, does it matter? |
#5
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"free" ip number when I remove device from database?
On 11 touko, 18:06, Sandroid wrote:
On 11 touko, 15:00, "PieterLinden via AccessMonster.com" u49887@uwe wrote: Sandroid wrote: Access 2007. Problem is when I delete the device (which has foreign key, ipID) from device table the IP number from IP table (has ID, primary key) also deletes (relation 1:1). *I want to "free" ip number when I remove device from database so IP number is not deleted and can be used later. How to accomplish this? I must be forgetting how to read... or not awake yet. *Do you have cascading deletes turned on between the two tables? *If so, turn it off. -- Message posted viahttp://www.accessmonster.com cascading turned off - no help referential integrity turned off - no help which way to create the relation from IP to Device or vice versa, does it matter? I don't want to delete IP address from tblIP, can I make tblIP lookup table then? how to make make sure that each ip address is used only once? tblIP structu ID(primary),ip, ip2, ip3, ip4. |
#6
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"free" ip number when I remove device from database?
On Tue, 11 May 2010 09:45:12 -0700 (PDT), Sandroid
wrote: I don't want to delete IP address from tblIP, can I make tblIP lookup table then? how to make make sure that each ip address is used only once? tblIP structu ID(primary),ip, ip2, ip3, ip4. Lookup tables do more harm than good! You can create a unique Index on the combination of the four ip fields; open the table in design view, select the Indexes tool (like lightning hitting a table), and type UniqueIP in the left column, and select IP in the right column. On the next three rows put IP2, IP3 and IP4 in the right column under IP. Check the Unique checkbox and it won't let you enter a duplicate IP. -- John W. Vinson [MVP] |
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