I need to filter data by substring, I mean, if I have got this data:
'John','Markus','james'
And i want to look by all elements which contains 'm' it should return:
'Markus','james'
Or if I filter by 'hn', the results should be:
'John'
How can I do it using CloudSearch or CloudQuery?
EDIT: I have seen wildcard method which seems to fit with my requirements, except for only is allowed a column (string) param. I would need to filter also by columns (array). As in searchOn method.
This should work I think. did you try it with this :
var query = new CB.CloudQuery('TableName');
//then you can:
query.substring('ColName','Text');
//or
query.substring(['ColName1','ColName2'],'Text');
//or
query.substring('ColName',['Text1', 'Text2']);
//or
query.substring(['ColName1','ColName2'],['Text1', 'Text2']);
query.find(callback);
Related
So I'm doing some tests with GraphQL, and I'm failing in doing something that I believe is fairly simple.
When going to the GraphQL demo site (https://graphql.org/swapi-graphql) I'm presented with a default query which goes like this:
{
allFilms {
films {
title,
director,
releaseDate
}
}
}
This works as expected and returns a list of films.
Now - I would like to modify this query to return only the films where the director is George Lucas, and for the life of me - I can't figure out how to do that.
I've tried using the where and filter expressions, and also change the second line to films: (director: "George Lucas") but keep getting error messages.
What's the correct syntax for doing that?
Thanks!
If you check the docs of the provided GraphQL schema, you'll see that this is not possible. Following is the definition of the allFilms field:
allFilms(
after: String
first: Int
before: String
last: Int
): FilmsConnection
As per the doc, it has 4 input arguments, which are after, first, before, and last. There is no way to filter this out using the director's name.
GraphQL is not SQL. You cannot use expressions like WHERE or FILTER in GraphQL. The schema is already defined and the filters are pre-defined too. If the schema does not allow you to filter values using a certain field, you just can't do it.
You can to see the graphql schema here https://github.com/graphql/swapi-graphql/blob/master/schema.graphql
The allFilms query does not contain a filter for the field director. Also i can't find other query with this filter.
Most likely you need to write a filter on the result of the query.
I am performing an Elasticsearch query using the high-level-rest-api for Java and expect to see records that are either active or do not have a reference id. I'm querying by name for the records and if I hit the index directly with /_search?q=, I see the results I want.
Is my logic correct (pseudo-code):
postFilters.MUST {
Should {
MustNotExist {referenceId}
Must {status = Active}
}
Should {
MustNotExist {referenceId}
Must {type = Person}
}
}
What I get are records that are active with a reference id. But, I want to include records that also do not have a referenceId, hence why I have MustNotExist {referenceId}.
For simplicity, the second Should clause can be dropped (for testing) as the first one is not working as expected by itself.
In my case, I had to use a match query instead of a term query because the value I was querying for was not a primitive or a String. For example, the part where Must, type = Person, Person was an enum, and so looking for "Person" was not quite right, whereas match allowed it to "match".
I'm building a advanced search functionality and, thanks to the help of some ruby fellows on SO, I've been already able to combine AND and OR conditions programmatically on different fields of the same class.
I ended up writing something similar to the accepted answer mentioned above, which I report here:
query = criteria.each_with_object({}) do |(field, values), query|
field = field.in if(values.is_a?(Array))
query[field] = values
end
MyClass.where(query)
Now, what might happen is that someone wants to search on a certain field with multiple criteria, something like:
"all the users where names contains 'abc' but not contains 'def'"
How would you write the query above?
Please note that I already have the regexes to do what I want to (see below), my question is mainly on how to combine them together.
#contains
Regex.new('.*' + val + '.*')
#not contains
Regex.new('^((?!'+ val +').)*$')
Thanks for your time!
* UPDATE *
I was playing with the console and this is working:
MyClass.where(name: /.*abc.*/).and(name: /^((?!def).)*$/)
My question remains: how do I do that programmatically? I shouldn't end up with more than two conditions on the same field but it's something I can't be sure of.
You could use an :$and operator to combine the individual queries:
MyClass.where(:$and => [
{ name: /.*abc.*/ },
{ name: /^((?!def).)*$/ }
])
That would change the overall query builder to something like this:
components = criteria.map do |field, value|
field = field.in if(value.is_a?(Array))
{ field => value }
end
query = components.length > 1 ? { :$and => components } : components.first
You build a list of the individual components and then, at the end, either combine them with :$and or, if there aren't enough components for :$and, just unwrap the single component and call that your query.
I have a legacy database that has data elements stored as a comma delimited list in a single database field. (I didn't design that, I'm just stuck with it.)
I have a list of strings that I would like to match to any of the individual values in the "array" in the DB field and am not sure how to do this in Linq.
My list:
List<string> items= new List<string>();
items.Add("Item1");
items.Add("Item2");
The DB field "Products" would contain data something like:
"Item1,Item3,Item4"
"Item3,Item5,Item6"
"Item2,Item7,Item6"
"Item1,Item2"
"Item1"
My first pass at the Linq query was:
var results = (from o in Order
.Where(p=> items.Contains(p.Products)
But I know that won't work. because it will only return the records that contain only "Item1" or "Item2". So with the example data above it would return 0 records. I need to have it return two records.
Any suggestions?
There is a simple clever trick for searching comma-separated lists. First, add an extra , to the beginning and end of the target value (the product list), and the search value. Then search for that exact string. So for example, you would search ,Item1,Item3,Item4, for ,Item1,. The purpose of this is to prevent false positives, i.e., Item12,Item3 finding a match for Item1, while allowing items at the beginning/end of the list to be properly found.
Then, you can use the LINQ .Any method to check that any item in your list is a match to the product list, like the following:
var results = (from o in Order
.Where(o => items.Any(i => (","+o.Products+",").Contains(","+i+",")))
One way would be to parse the list in the Products field:
var results = (from o in Order
.Where(o => items.Any(i => o.Products.Split(',').Contains(i))
But that would parse the string multiple times for each record. You could try pulling back ALL of the records, parsing each record once, then doing the comparison:
var results = from o in Order
let prods = o.Products.Split(',')
where items.Any(i => prods.Contains(i))
select o;
I have a data table containing multiple columns and one column that stores somewhat complex text patterns - I need to parse the field to determine if a particular sub strings exist in specific positions within the larger string pattern and then if the record should be filtered out as a result.
I can't see a way to perform the parse other than by writing a C# parsing function with String.Split method calls, foreach, etc. But if I try to parse like this:
var myFilteredTable = _db.MyTable.Where(t => t.Column1 == 'Filter1'
&& ParseIsMyItemInColumn2(t) );
I get "has no supported translation to SQL" errors.
The other option I thought of was to build the initial result without the Parse:
var myFilteredTable = _db.MyTable.Where(t => t.Column1 == 'Filter1' );
and iterate through the IQueryable resultset, testing each row with the parse function, to filter out the unwanted rows, but IQueryable does not have Remove function to strip out unwanted rows nor Add function to allow me to build up a new resultset.
So how can I filter in linq when I also need to write a Parse function?
Well the "initial filter in the database then do the rest locally" is easy:
var filtered = _db.MyTable.Where(t => t.Column1 == "Filter1")
.AsEnumerable() // Do the rest locally
.Where(t => ParseIsMyItemInColumn2(t));
AsEnumerable is a simple pass through method, but because the result is typed as IEnumerable<T> rather than IQueryable<T>, the subsequent LINQ operations use the LINQ to Objects methods in Enumerable rather than the ones in Queryable.
Obviously if a lot of items match the first filter but fail the second, that won't be terribly efficient...
Unfortunately, if the "parse function" is not something that can be translated to SQL, you will need to pull the results and use LINQ to Objects:
var myFilteredTable = _db.MyTable.Where(t => t.Column1 == 'Filter1')
.AsEnumerable().Where(ParseIsMyItemInColumn2);
Note that this will stream all of the results into memory, and then perform your parse.