IQueryable
IQueryable is a .NET interface representing a queryable data source whose expression trees can be translated and executed by a provider.
Building Web APIs with ASP.NET Core
IQueryable<T> is a generic .NET interface representing a queryable data source of a specified element type whose query can be composed and translated by a provider.
- How it is used
- Uses IQueryable<T> to compose EF Core database reads in API controllers and expose queryable DbSets to GraphQL.
- How deep it goes
- Explains DbSet<T> implementation, LINQ composition, expression-tree translation, and execution with ToArray(), without detailing translation internals.
- Examples
- Demonstrates filtering board games by year, sorting by name, fetching a controller response, and returning DbSets from GraphQL query methods.
- What you can do after
- Apply it via EF Core to compose and execute controller queries or provide queryable sources for HotChocolate GraphQL methods.
Read how Building Web APIs with ASP.NET Core explains IQueryable →
.NET in Action, Second Edition
IQueryable is a LINQ interface representing a queryable data source whose query expression can be interpreted by a provider.
- How it is used
- Uses IQueryable to compose EF Core catalog queries as request filters, sorting, and paging vary.
- How deep it goes
- Defines IQueryable through IEnumerable and demonstrates DbSet queries, but does not explain provider internals.
- Examples
- Shows an ordered Book query after SaveChanges() and a catalog GET action initialized with IQueryable<Book>.
- What you can do after
- Apply it via EF Core to compose catalog queries and add request-controlled sorting and paging.
Read how .NET in Action, Second Edition explains IQueryable →
Pro ASP.NET Core 7, Tenth Edition
IQueryable<T> is a .NET interface representing a queryable sequence whose query operations can be translated and executed by an underlying data provider.
- How it is used
- Exposes database-backed objects through a repository and lets Blazor components compose queries before fetching results.
- How deep it goes
- Explains query composition, database execution, and repeated enumeration through repository and component examples, without detailing provider translation internals.
- Examples
- Shows an IQueryable<Product> repository property and Sort buttons that contrast a new database query with sorting existing results.
- What you can do after
- Apply it via Entity Framework Core to compose queries and recognize when enumeration or sorting sends another database request.
Read how Pro ASP.NET Core 7, Tenth Edition explains IQueryable →
ASP.NET Core in Action, 3e
IQueryable is a .NET interface for representing queries whose expression trees can be translated and executed by a data source.
- How it is used
- Represents composable database queries that EF Core translates into SQL before retrieving records.
- How deep it goes
- Explains composition, SQL translation, execution methods, projection, and limited client-side evaluation without covering provider internals.
- Examples
- Uses a RecipeService query that filters deleted recipes, projects RecipeSummaryViewModel objects, and calls ToListAsync().
- What you can do after
- Apply it via EF Core to filter, project, and asynchronously load database records efficiently.
Related concepts
- DbSet<T>includes · DbSet<T> is an Entity Framework Core type representing a queryable and persistable set of entities of type T within a database context.
- IEnumerable<T>kind of · IEnumerable<T> is a .NET generic interface representing a sequence whose elements of type T can be traversed through an enumerator.
- expression treeproduces · An expression tree is a hierarchical data structure whose nodes represent the operations, operands, functions, and values of an expression.
- IEnumerablekind of · IEnumerable is a .NET interface representing a sequence whose elements can be traversed through an enumerator.
- SQLproduces · SQL is a standardized declarative language for defining, querying, and manipulating data and structures in relational database systems.
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