Special Ledger Screws
Because of the tedious process involved in drilling several pilot holes in the wood to use lag screws, there are a few products available that are designed for the specific purpose of attaching a deck ledger to a building. One such fastener is the FastenMaster LedgerLok®, which is pictured above. Simpson Strong-Tie makes a similar fastener, called the Strong-Drive® SDS Screw. These fasteners are designed to be installed without any pilot holes, and they already come with a washer attached to each head.
While these fasteners may cost a little more, they're fast and easy to install, and they're code approved to be used in place of 1/2" lag screws.
Through-bolts can be used to attach a ledger to the house when the interior of the rim joist is accessible. This is typically done using carriage bolts, pictured above. When through-bolts are used, you'll either see the head of the bolt or the end of the bolt at the ledger. Lag bolts work in a similar manner.
All things being equal, a through bolt makes for the strongest connection per fastener. Without all things being equal, there are certainly ways of installing through-bolts improperly. In the examples below, you can see the end of the bolt where a washer and nut were fastened. The problem with this installation is that someone didn't have long enough bolts, so they had to chisel out a bunch of holes in the ledger to sink the washers and nuts in to.
This is probably the least common method of deck attachment because it takes more time, and requires more running in and out of the building.