I am trying to use memcached for the first time but I have a few questions when it comes to queries with dynamic variables.
This is a sample of my code so far. I got everything working but if you see any mistakes on my code please let me know.
<cfoutput>
<cfset variables.memcachedFactory = createObject("component","memcachedfactory").init("127.0.0.1:11211")>
<cfset variables.memcached = variables.memcachedFactory.getmemcached()>
<cfset email = "sbcglobal"> //Pretend that this is a list with multiple choices for the user to choose from.
//The query below would have multiple outputs based on the selection of the user above
<cfquery name="test" datasource="#ds#">
select top 10 * from contact where email like '%#email#%'
</cfquery>
//Setting the key
<cfset set100 = variables.memcached.set(key="queryTest2",value=test,expiry="5000")>
//Getting the key
<Cfset test6 = variables.memcached.get("queryTest2")>
<br><br>this is the query test - did we retrieve it correctly? - <br />
<Cfdump var="#Test6#"><br />
</cfoutput>
Now, do i have to set a key for every possible outcome of the query? (which in my case would be a few hundred keys to cover all possible outcomes)
My understanding is that memcached saves the value to a key after the first request and after that you get the output without db calls.
If I use memcached in my case would it just be a waste of code since each query would be different based on the user's choice?
Also, how do you update the values in cache in case the output changes? Is this something that I would have to do manually? My database get 100's of transactions daily, a select * from contacts at 10 am will not have the same output at 5pm
The idea behind caching (in this case) is that you first check memcached, and if the key exists, you get the data from the cache. If it doesn't exist, you go to the database, get the data, stick it in memcached, then return it to the user.
For your use case here, you want a unique key for each unique record set you're returning. Take your example. If email address is the unique key you are using to identify a record set, then use that as the key in memcached. Pseudo-code:
<cfset results = variables.memcached.set(key="foo_#email#",value=test,expiry="5000")>
foo_ lets you provide a "namespace" for the keys you are putting into memcached, which makes it easier to manage and avoid key collisions.
Related
We have a three-panel display in which Panel One shows a list of countries, Panel Two shows a list of organizations, and Panel Three shows a list of aircraft. If you click a country, both the organizations and aircraft are filtered by that country, using IDs for each.
This is all working fine, but the list of aircraft comes from a "linking table" -- each record contains aircraft ID and name, and operator ID and name. Any given type of aircraft can be listed multiple times, depending on how many organizations operate it. For example, "AW159 Wildcat" is listed twice, once for Army Air Corps and once for Royal Navy. The way it works right now, "AW159" is listed in Panel Three twice when the page initially loads.
I would like any given aircraft to be displayed only once on initial page load, regardless of how many times it may be listed in this linking table. But, I want all the "duplicates" available to be shown, if somebody filters on the operating organization.
Is there a way to loop over all the aircraft but somehow hide duplicates of aircraft ID? Or, might there be a larger problem with the way our database is designed? I am open to suggestions. Thank you all very much in advance!
EDIT: sorry for not posting code; here is some. Thanks everybody for all of your help!
1. Query and array population in cfc:
<cfquery name="queryByOperator" datasource="vertipedia">
SELECT view_aircraftbyoperators.aircraftID
, view_aircraftbyoperators.Aircraft
, view_aircraftbyoperators.operatorID
, view_aircraftbyoperators.Operator
, tbl_companies.country
, tbl_companies.companyShortName
FROM view_aircraftbyoperators JOIN tbl_companies
ON tbl_companies.ID = view_aircraftbyoperators.operatorID
ORDER BY Aircraft
</cfquery>
<cfset count = 1>
<cfset aircraftByOperator = arrayNew(2)>
<cfloop query="queryByOperator">
<cfset aircraftByOperator[count][1] = aircraftID>
<cfset aircraftByOperator[count][2] = Aircraft>
<cfset aircraftByOperator[count][3] = operatorID>
<cfset aircraftByOperator[count][4] = Operator>
<cfset aircraftByOperator[count][5] = country>
<cfset count = count+1>
</cfloop>
2. Outputting on page:
<ul>
<cfloop from="1" to="#ArrayLen(aircraftByOperator)#" index="i">
<cfoutput>
<li name="#aircraftByOperator[i][3]#" class="#aircraftByOperator[i][5]#">
<p>
#aircraftByOperator[i][2]#
</p>
</li>
</cfoutput>
</cfloop>
</ul>
[i][1], [i][3] and [i][5] are all IDs. "operatorID" is the one that will change depending on who operates the aircraft. I hope this helps explain what I am trying, and again, many thanks!
Dan Bracuk's comment "Does this mean you are pre-loading all your data into javascript? It might be more efficient to throw some ajax in there and just get what you need when you need it" ended up being the way to go for us. I would like to mark his comment as the answer, but am unable to see how to do that.
For others who may read this post, we
Loaded all of the aircraft initially
When a visitor filters by country and/or organization, a new query is sent via ajax
I was having a hard time formatting the returned data, so I used jQuery's load() to format it and drop it in the proper place in the output panel.
As Dan said, it is very fast and much easier to work with, especially as our database continues to grow.
Thanks Dan!
Inside a cffunction I have a query that I want to long cache by setting the cachedwitin to a big value. However, I also want to clear that cache under a few circumstances.
I've done this in a number of places, but in one of them the cache is never updated and I always get the original value if I ask it to give me the cached value.
The cfquery documentation states:
To use cached data, the current query must use the same SQL statement, data source, query name, user name, and password.
This is the case with the query, since it's a single sql statement with no non-sql except the cfqueryparam; datasource and query name don't change and username and password are not specified.
The relevant code is:
<!--- Long cache the query since the values rarely change, but allow the cache to be cleared. --->
<cfif Arguments.ClearCache EQ false>
<cfset local.CachedWithin = CreateTimeSpan(7,0,0,0)>
<cfelse>
<cfset local.CachedWithin = CreateTimeSpan(0,0,0,-1)>
</cfif>
<cfquery name="local.qryName" datasource="#Variables.DSN#" cachedwithin="#local.CachedWithin#">
SELECT
[User].[Name]
FROM
[User]
WHERE
[User].[UserID] = <cfqueryparam value="#Arguments.UserID#" cfsqltype="cf_sql_integer">
</cfquery>
Why does this work in other places, but not here?
There is an additional "sameness" requirement for cached queries that isn't mentioned in the documentation. That note should end with:
... password, and underlying data types of any cfqueryparam values.
Change your code so that the Arguments.UserID is forced to a data type. In your case this can be accomplished by putting the following code before the cfquery:
<!--- Make sure data types used in query are consistent --->
<cfset local.UserID = Int(Arguments.UserID)>
and change the cfqueryparam value to value="#local.UserID#".
I've phrased the above as an omission in the documentation, but I suspect it's a bug in CF9 instead.
I have a coldfusion application running right now with a login that sends a query to the database looking for a row with the same username and password as what was entered into the form.
Curently, it is completely non-case sensitive. However, I would like to add case sensitivity to the password field, so that users have to have the exact password. Is there a way to do a case sensitive IF statement in coldfusion?
You can hash() both values and compare the hashes.
<cfif Hash( DBPassword ) EQ Hash( SubmittedPassword )>
<!--- Login Code --->
</cfif>
Also, you shouldn't be storing passwords as plain-text in the databases as is.
As mentioned here:
http://www.irt.org/script/3018.htm
seems you can use:
<cfif Compare(string1,string2) eq "0">...</cfif>
Another option:
If your database supports case-sensitivity, set your table to use a case-sensitive collation - then your user lookup query will make case-sensitive comparison of stored and provided username/password. You won't have to do any post-query string comparison using CF then (1 less process to run = good :)
+1 to Leigh's caution about storing passwords in plain-text.
I'm working with a query that has a column named "Date."
The original query returns okay from the database. You can output the original query, paginate the original query, get a ValueList of the Date column, etc.
Query of Query
<cfquery name= "Query" dbtype= "query">
select
[Query].[Date]
from [Query]
</cfquery>
Response from ColdFusion
Query Of Queries syntax error. Encountered "Date. Incorrect Select
List,
Typically, I use descriptive names so I haven't run across this issue previously.
In this case, I'm working with a stored procedure that someone else wrote. I ended up modifying the stored procedure to use a more descriptive column name.
I have a service I use for transforming, searching and sorting queries with ColdFusion. I'm curious to know the answer to my original question, so that I can modify my service to either throw a better error or handle reserved words.
Is there a way to escape and use ColdFusion query reserved words as column names in a query of query?
The following code works fine for me:
<cfset query = queryNew("date")>
<cfdump var="#query#">
<cfquery name= "Query" dbtype= "query">
select
[Query].[Date]
from [Query]
</cfquery>
<cfdump var="#query#">
In standard mysql you'd "escape" the fields by using the ` character.
So for example:
select `query`.`date` from `query`
Try that and see if it works?
Why does this not work? My welcome message, it just doesn't show up:
<p>Welcome <cfoutput>#Recordset1.UserID#</cfoutput>.</p>
The session variable on the login page I created is:
<cflock timeout=999 scope="Session" type="Exclusive">
<cfset Session.IDUsers =''>
</cflock>
is this incorrect? On the index page where I'm trying to display my welcome message I have:
<cfquery name="Recordset1" datasource="cfGossip">
SELECT *
FROM users
WHERE users.IDUsers = <cfqueryparam value="#Session.IDUsers#">
</cfquery>
I'm not sure if this works, or is necessary?
If you set the userid stored in the session to be the empty string, when you query on it, you will only get users for whom the id is the empty string, which shouldn't be any of them. Therefore, the query is returning an empty set, and your page is (correctly) not displaying a user id.
How are you initially identifying the user? Are you querying against a database when they log in? Are you storing a cookie? Reading Tarot cards? For this to work, at some point, you have to store the correct userid, probably in the session. To do that, you need to first identify who the user is.
Also, if you are using CF6+, you probably do not need the cflock. It is now used to prevent race conditions, as CF is now thread-safe.
Looks like you're just starting with CF, welcome to the community.
My understanding of your code makes the structure look like the following, if I'm understanding you correctly:
<cfset session.idUsers = '' />
<cfquery datasource = "cfgossip" name = "recordset1">
SELECT * FROM USERS WHERE USERS.ID_USERS = <cfqueryparam cfsqltype = "cf_sql_integer" value = "#session.idUsers# />
</cfquery>
<cfoutput>Welcome #recordset1.userID#</cfoutput>
The reason this doesn't work is because your session.idUsers value is blank. Assuming you have a user in your database with an ID_USERS value of 1, you could change the CFSET to look like and it should return results.
Additionally, while it's great to see you using CFQUERYPARAM, I'd recommend including a CFSQLTYPE attribute in the tag whenever possible to provide an added line of defense against injection attacks. You can check out http://livedocs.adobe.com/coldfusion/8/htmldocs/help.html?content=Tags_p-q_18.html to see the list of available types.
Is there anywhere in your code where you set your session.IDUsers? You initialize it as a blank ''. Coldfusion does not populate it for you. The session scope is a place that will remember things for that user that you put there for a specified period of time inactivity, usually 20 minutes. So hopefully, somewhere before you run your query you have additional logic that fills that in, otherwise you are asking the database for a user named, ''.
This is just a point of style, but the following may work better for you:
<cfset Session.IDUsers =''>
<!--- Do something here to populate Session.IDUsers --->
<!--- Creates a blank query - not necessary, but can reduce errors later --->
<cfset Recordset1 = queryNew("UserID")>
<!--- Populate the query from the database --->
<cfquery name="Recordset1" datasource="cfGossip">
SELECT *
FROM users
WHERE users.IDUsers = <cfqueryparam value="#Session.IDUsers#">
</cfquery>
<!--- If the query has data, use it, otherwise show generic message --->
<cfoutput>
<cfif Recordset1.recordcount>
<p>Welcome #Recordset1.UserID#.</p>
<cfelse>
<p>Welcome new user!</p>
</cfif>
</cfoutput>
<!--- OR since we used queryNew("userID"), we can simplify without throwing an error. ---->
<cfoutput>
<p>Welcome <cfif len(Recordset1.userID)>#Recordset1.userID#.<cfelse>new user!</cfif></p>
</cfoutput>
Putting the cfoutput outside the paragraph block will make it easier if you have additional variables to insert into the text. (but will work either way)
Regardless of all that, unless you forgot to share a bit more of the code, I think the issue is that the session.IDUsers is blank and needs to be populated before the query. I hope this helps!