Basic LINQ queries
This book is not intended to be a LINQ handbook. However, we will show you some basic LINQ queries in this section:
- Querying the data
- Filtering the data
- Sorting the data
- Paging the data
- Creating the data
- Updating the data
- Deleting the data
Querying the data
The DbSet<Invoice> Invoices property in the InvoiceDbContext class represents a collection of the Invoice entity. We can use LINQ methods to query the data. For example, we can use the ToListAsync() method to retrieve all the invoices from the database:
var invoices = await _context.Invoices.ToListAsync();
That is how the GetInvoices action method works.
To find a specific invoice, we can use the FindAsync() method, as shown in the GetInvoice() action method:
var invoice = await _context.Invoices.FindAsync(id);
The FindAsync() method accepts the primary key value as the parameter. EF Core will translate the FindAsync() method to the SQL SELECT statement...
