I want to make sure I am formatting the right way the clause like in a query. For example, I have the following code:
int count = [[[MyDBObject query] whereWithFormat:#"url like '%%#%'", mySearchString] count];
My question is: am I using the correct formatting for like clause ?
Thank you and happy coding :)
Because the string formatter hates this we had to adapt and make a special parameter type, so we can identify it as a like parameter. Because string formatting is one part, but then the parameters are then supplied to the query the formatting gets quite screwed up and you have to get quite inventive with the escape characters.
So the thing you need is dbMakeLike()
Example:
whereWithFormat:#"lower(text) LIKE %#“, dbMakeLike(searchString.lowercaseString)
Thanks
Related
I am currently using this formula to get all the data from everyone whose first name is "Peter", but my problem is that if someone is called "Simon Peter" this data is gonna show up on the formula output.
=QUERY('Data'!1:1000,"select * where B contains 'Peter'")
I know that for the other formulas if I add an * to the String this issue is resolved. But in this situation for the QUERY formula the same logic do not applies.
Do someone knows the correct syntax or a workaround?
How about classic SQL syntax
=QUERY('Data'!1:1000,"select * where B like 'Peter %'")
The LIKE keyword allows use of wildcard % to represent characters relative to the known parts of the searched string.
See the query reference: developers.google.com/chart/interactive/docs/querylanguage You could split firstname and lastname into separate columns, then only search for firstnames exactly equal to 'Peter'. Though you may want to also check if lowercase/uppercase where lower(B) contains 'peter' or whitespaces are present in unexpected places (e.g., trim()). You could also search only for values that start with Peter by using starts with instead of contains, or a regular expression using matches. – Brian D
It seems that for my case using 'starts with' is a perfect fit. Thank you!
Im having issues with rails with the code
if #turno.chop == res[:department].to_s
where turno contains strings like ABC1 and department like ABC, im trying to filter if turno its equal of department but i need reduce the string of turno for that.
Every time what i try to do that the code dont finish and stuck in other part of code, when i delete the condition, the code works perfectly but dont do the filter.
i tryid to to do like
if #turno.include?(res[:department].to_s)
But appears the same error.
I believe something very similar to this was answered in the stackoverflow.com question. How to check whether a string contains a substring in Ruby?
The include? command sounds like what you should use.
my_string = "abcdefg"
if my_string.include? "cde"
puts "String includes 'cde'"
end
To be more accurate, #turno can contain a string like "ABC1" and res[:department] contains a string with "ABC" i need reduce the string in #turno to the first X characters and compare it with the content of res[:department]
I have array of strings:
a = ['*#foo.com', '*#bar.com', '*#baz.com']
I would like to query my model so I will get all the records where email isn't in any of above domains.
I could do:
Model.where.not(email: a)
If the list would be a list of strings but the list is more of a regexp.
It depends on your database adapter. You will probably be able to use raw SQL to write this type of query. For example in postgres you could do:
Model.where("email NOT SIMILAR TO '%#foo.com'")
I'm not saying thats exactly how you should be doing it but it's worth looking up your database's query language and see if anything matches your needs.
In your example you would have to join together your matchers as a single string and interpolate it into the query.
a = ['%#foo.com', '%#bar.com', '%#baz.com']
Model.where("email NOT SIMILAR TO ?", a.join("|"))
Use this code:
a = ['%#foo.com', '%#bar.com', '%#baz.com']
Model.where.not("email like ?",a.join("|"))
Replace * to % in array.
I am using rails with a postgresql db, and I would like to know which is the best solution, in getting all the rows which are similar with a string.
string format: domain.com or domain.com/uk or subdomain.domain.com
db column format : http://www.test.com/All-test/test1/test2-test3/
So I would like to get from my table all the rows which are matching with my string.
Currently I have a script which is going through all the rows in my table, and taking the column values, from where it takes the host and compares it with the string.
Thank you
Looks like the LIKE function is what you want to use. You can use in in an ActiceRecord query like this:
search_string = "domain.com"
YourModel.where("db_column LIKE ?", "%#{search_string}%").first
You might need to refine the search, but the link above should give you all the tools you need
Say I have a collection of users and want to implement autocomplete on the usernames of those users. I looked at the mongodb docs and $regex seems to be one way to do this. Is there a better way? By better I mean more performant/better practice.
As suggested by #Thilo, you can use several ideas including prefixing.
The most important thing is to have very quick request (because you want autocomplete to feel instaneous). So you have to use query which will use properly indexes.
With regexp : use /^prefix/ (the important thing is the ^ to specify the beginning of line which is mandatory to make the query use index).
The range query is good too : { $gt : 'jhc', $lt: 'jhd' } }
More complicated but faster : you can store prefix-trees in mongo (aka tries) with entries like :
{usrPrefix : "anna", compl : ["annaconda", "annabelle", "annather"]}
{usrPrefix : "ann", compl : ["anne", "annaconda", "annabelle", "annather"]}
This last solution is very fast (if indexes on compl of course) but not space efficient at all. You know the trade-off you have too choose.
We do it using regex and it's fast as long as you have an index and you use /^value/
Be aware you can't use the case insensitive option with an index, so you may want to store a lower case version of your string as another field in your document and use that for the autocomplete.
I've done tests with 3 million+ documents and it still appears instantaneous.
If you are looking for prefixes, you could use a range query (not sure about the exact syntax):
db.users.find({'username': { $gt : 'jhc', $lt: 'jhd' } } )
And you want an index on the username field.