LiteDB.Queryable

An IQueryable wrapper implementation for LiteDB with additional async extensions.

This library allows the use of LINQ extensions methods for querying LiteDB.

The LiteQueryable<T> implementation is a warpper around a ILiteCollection<T> or a ILiteCollectionAsync<>. The LINQ extenions call are delegated to the equivalent methods of the LiteDB API.

Usage

Add the NuGet package to your project: LiteDB.Queryable

You can then aquire an IQueryable<T> instance using one of the available AsQueryable extension methods for ILiteCollection<T> or ILiteCollectionAsync<T>. The async variant is provided by the litedb-async project.

LiteDatabase database = new LiteDatabase("test.db");
ILiteCollection<Person> collection = database.GetCollection<Person>("people");
IQueryable<Person> queryable = collection.AsQueryable();

or

LiteDatabaseAsync database = new LiteDatabaseAsync("test.db");
ILiteCollectionAsync<Person> collection = database.GetCollection<Person>("people");
IQueryable<Person> queryable = collection.AsQueryable();

After that you can use the synchronous LINQ extensions with both variants and the asynchronous ones with the second variant.

Supported LINQ extensions

You can use the following methods to configure your query. Those methods are available in both variants.

• Where
• OrderBy
• OrderByDescending
• Skip
• Take
• Include
• Select

The ThenBy/ThenByDescending methods and multiple OrderBy/OrderByDescending class are not supported at the moment, because LiteDB doesn't support multiple order exprssions.

Synchronous extenions

• ToList
• ToArray
• ToDictionary
• First
• FirstOrDefault
• Single
• SingleOrDefault
• Count
• LongCount
• Any
• Sum
• Average
• Min
• Max

Asynchronous extenions

• ToListAsync
• ToArrayAsync
• ToDictionaryAsync
• FirstAsync
• FirstOrDefaultAsync
• SingleAsync
• SingleOrDefaultAsync
• CountAsync
• LongCountAsync
• AnyAsync
• SumAsync
• AverageAsync
• MinAsync
• MaxAsync

Example

LiteDatabase database = new LiteDatabase("test.db");
ILiteCollection<Person> collection = database.GetCollection<Person>("people");
IQueryable<Person> queryable = collection.AsQueryable();

IList<Person> result = queryable
	.Where(x => x.Name.StartsWith("T"))
	.OrderBy(x => x.Age)
	.ToList();

Person result = queryable
	.Where(x => x.Age > 35)
	.FirstOrDefault();

string result = queryable
	.Where(x => x.Age > 35)
	.Select(x => x.Name)
	.FirstOrDefault();

or

LiteDatabaseAsync database = new LiteDatabaseAsync("test.db");
ILiteCollectionAsync<Person> collection = database.GetCollection<Person>("people");
IQueryable<Person> queryable = collection.AsQueryable();

IList<Person> result = await queryable
	.Where(x => x.Name.StartsWith("T"))
	.OrderBy(x => x.Age)
	.ToListAsync();

Person result = await queryable
	.Where(x => x.Age > 35)
	.FirstOrDefaultAsync();

string result = await queryable
	.Where(x => x.Age > 35)
	.Select(x => x.Name)
	.FirstOrDefaultAsync();

References

• LiteDB
• LiteDB Async
• Entity Framework Core