- The ledger is subjective from each peer’s perspective
- Two peers are always guaranteed to see the exact same version of any on-ledger facts they share
The Ledger Data¶
In Corda, there is no single central store of data. Instead, each node maintains its own database of those facts that it is aware of.
The facts that a node knows about are those that it is involved with. For example, if there are nodes representing Alice and Bob on the network and Alice loans Bob some money, both Alice and Bob will store an identical record of the facts about that loan. If the only parties involved with the loan are Alice and Bob, then they will be the only nodes that ever see or store this data.
Important: The result of this design is that each peer only sees a subset of facts on the ledger, and no peer is aware of the ledger in its entirety.
Example: A network with five nodes, where each numbered circle on an intersection represents a fact shared between two or more nodes.
The preceding Venn diagram represents 5 nodes (Alice, Bob, Carl, Demi and Ed) as sets. Where the sets overlap are shared facts, such as those known by both Alice and Bob (1 and 7).
Notably, in this Venn diagram, Alice only shares facts with Bob. Alice does not share facts with any of Carl, Demi or Ed.
The Corda Ledger is a subjective construct from each peer’s point of view.
What does that mean?
- There are no omniscient peers who can see everything on the ledger.
- Each node sees their own facts, and the facts that they share with others.
For example, Alice and Demi don’t share any facts, so they each see a completely different set of shared facts.