Linq List Contains

Question

I am using ArangoDB and I am querying a collection named movies. Its data structure is such that categories is a List of strings.

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public class movies
{
    [DocumentProperty(Identifier = IdentifierType.Key)]
    public string Key;
    public List<string> categories;
    public string desc;
    public string img;
    public List<vod_stream> streams;
    public string title;
};

Here is the query statement:

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var result = db.Query<movies>()
            .Where(p => p.categories.Contains(id));

id is passed as a param and I need to retrieve all the movies that has the category matched by the id. However, above code doesn't work as result gives me ALL the movies in the collection.

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foreach (movies mov in result)
{
    if (mov.categories.Contains(id) == false)
    { continue; }

    // do something here
}

The weird thing is when I loop through the items in the result, the same function does return false for some of the items. But it just doesn't work in the Linq statement.

Anybody knows what is wrong with my query statement?

Answer 1

For using AQL Functions in ArangoDB LINQ provider you should use ArangoDB.Client.AQL static methods.

For your use-case you can use in AQL function:

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var result = db.Query<movies>()
                .Where(p => AQL.In(id, p.categories))
                .ToList();

which translates to :

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for `p` in `movies`  filter  @P1 in `p`.`categories`  return   `p`

Built-in methods for c# data structures like List are not currently supported in ArangoDB LINQ provider