Key-Value Store

The key-value store represents the internal state of the network. It is used by applications to store data to and read from the ledger.

Note

The pages below describe the C++ API. The experimental Rust SDK exposes only raw-byte maps; see Handler rules.

• Key-Value Store How-To
  • Map Naming
  • Transaction Semantics
  • Accessing Map content via a Handle
  • Read/Write safety
  • Removing a key
  • Global commit
  • Miscellaneous
    • foreach()
    • Applying and reverting writes
• Key-Value Serialisation
  • Custom key and value types
• Key-Value Store API
  • Map
    • Version
    • NoVersion
    • ccf::kv::TypedMap
    • Map
    • ccf::kv::TypedValue
    • Value
    • ccf::kv::TypedSet
    • Set
  • Transaction
    • ccf::kv::ReadOnlyTx
      • ro()
      • ro()
    • ccf::kv::Tx
      • rw()
      • rw()
      • wo()
      • wo()
  • Handles
    • ccf::kv::ReadableMapHandle
      • get_name_of_map()
      • get()
      • get_globally_committed()
      • has()
      • get_version_of_previous_write()
      • foreach()
      • foreach_key()
      • foreach_value()
      • size()
    • ccf::kv::WriteableMapHandle
      • put()
      • remove()
      • clear()
    • ccf::kv::MapHandle
    • ccf::kv::ReadableValueHandle
      • get()
      • get_globally_committed()
      • has()
      • get_version_of_previous_write()
    • ccf::kv::WriteableValueHandle
      • put()
      • clear()
    • ccf::kv::ValueHandle
    • ccf::kv::ReadableSetHandle
      • contains()
      • contains_globally_committed()
      • get_version_of_previous_write()
      • foreach()
      • size()
    • ccf::kv::WriteableSetHandle
      • insert()
      • remove()
      • clear()
    • ccf::kv::SetHandle
  • Serialisation
    • EntryType
      • WriteSet
      • Snapshot
      • WriteSetWithClaims
      • WriteSetWithCommitEvidence
      • WriteSetWithCommitEvidenceAndClaims
      • MAX
• KV Implementation Model
  • Observation contract
  • Current and globally committed views
  • Local application, commitment, and rollback
  • Proof and trust boundaries
  • Trace format and diagnostics
  • Reproducing a run
  • Seeded concurrent campaigns