Documentation ¶
Overview ¶
Package rawdb contains a collection of low level database accessors.
Index ¶
- Constants
- Variables
- func DeleteBlock(db DatabaseDeleter, hash common.Hash, number uint64) error
- func DeleteBody(db DatabaseDeleter, hash common.Hash, number uint64) error
- func DeleteCXReceiptsProofSpent(db DatabaseDeleter, shardID uint32, number uint64) error
- func DeleteCanonicalHash(db DatabaseDeleter, number uint64) error
- func DeleteCrossLinkShardBlock(db DatabaseDeleter, shardID uint32, blockNum uint64) error
- func DeleteCxLookupEntry(db DatabaseDeleter, hash common.Hash) error
- func DeleteHeader(db DatabaseDeleter, hash common.Hash, number uint64) error
- func DeleteReceipts(db DatabaseDeleter, hash common.Hash, number uint64) error
- func DeleteTd(db DatabaseDeleter, hash common.Hash, number uint64) error
- func DeleteTxLookupEntry(db DatabaseDeleter, hash common.Hash) error
- func DeleteValidatorSnapshot(db DatabaseDeleter, addr common.Address, epoch *big.Int) error
- func DeleteValidatorStats(db DatabaseDeleter, addr common.Address) error
- func FindCommonAncestor(db DatabaseReader, a, b *block.Header) *block.Header
- func HasBody(db DatabaseReader, hash common.Hash, number uint64) bool
- func HasHeader(db DatabaseReader, hash common.Hash, number uint64) bool
- func ReadBlock(db DatabaseReader, hash common.Hash, number uint64) *types.Block
- func ReadBlockCommitSig(db DatabaseReader, blockNum uint64) ([]byte, error)
- func ReadBlockRewardAccumulator(db DatabaseReader, number uint64) (*big.Int, error)
- func ReadBloomBits(db DatabaseReader, bit uint, section uint64, head common.Hash) ([]byte, error)
- func ReadBody(db DatabaseReader, hash common.Hash, number uint64) *types.Body
- func ReadBodyRLP(db DatabaseReader, hash common.Hash, number uint64) rlp.RawValue
- func ReadCXReceipt(db DatabaseReader, hash common.Hash) (*types.CXReceipt, common.Hash, uint64, uint64)
- func ReadCXReceipts(db DatabaseReader, shardID uint32, number uint64, hash common.Hash) (types.CXReceipts, error)
- func ReadCXReceiptsProofSpent(db DatabaseReader, shardID uint32, number uint64) (byte, error)
- func ReadCanonicalHash(db DatabaseReader, number uint64) common.Hash
- func ReadChainConfig(db DatabaseReader, hash common.Hash) *params.ChainConfig
- func ReadCrossLinkShardBlock(db DatabaseReader, shardID uint32, blockNum uint64) ([]byte, error)
- func ReadCxLookupEntry(db DatabaseReader, hash common.Hash) (common.Hash, uint64, uint64)
- func ReadDatabaseVersion(db DatabaseReader) int
- func ReadDelegationsByDelegator(db DatabaseReader, delegator common.Address) (staking.DelegationIndexes, error)
- func ReadEpochBlockNumber(db DatabaseReader, epoch *big.Int) (*big.Int, error)
- func ReadEpochVdfBlockNum(db DatabaseReader, epoch *big.Int) ([]byte, error)
- func ReadEpochVrfBlockNums(db DatabaseReader, epoch *big.Int) ([]byte, error)
- func ReadHeadBlockHash(db DatabaseReader) common.Hash
- func ReadHeadFastBlockHash(db DatabaseReader) common.Hash
- func ReadHeadHeaderHash(db DatabaseReader) common.Hash
- func ReadHeader(db DatabaseReader, hash common.Hash, number uint64) *block.Header
- func ReadHeaderNumber(db DatabaseReader, hash common.Hash) *uint64
- func ReadHeaderRLP(db DatabaseReader, hash common.Hash, number uint64) rlp.RawValue
- func ReadPendingCrossLinks(db DatabaseReader) ([]byte, error)
- func ReadPreimage(db DatabaseReader, hash common.Hash) []byte
- func ReadReceipt(db DatabaseReader, hash common.Hash) (*types.Receipt, common.Hash, uint64, uint64)
- func ReadReceipts(db DatabaseReader, hash common.Hash, number uint64) types.Receipts
- func ReadShardLastCrossLink(db DatabaseReader, shardID uint32) ([]byte, error)
- func ReadShardState(db DatabaseReader, epoch *big.Int) (*shard.State, error)
- func ReadStakingTransaction(db DatabaseReader, hash common.Hash) (*staking.StakingTransaction, common.Hash, uint64, uint64)
- func ReadTd(db DatabaseReader, hash common.Hash, number uint64) *big.Int
- func ReadTransaction(db DatabaseReader, hash common.Hash) (*types.Transaction, common.Hash, uint64, uint64)
- func ReadTxLookupEntry(db DatabaseReader, hash common.Hash) (common.Hash, uint64, uint64)
- func ReadValidatorList(db DatabaseReader) ([]common.Address, error)
- func ReadValidatorSnapshot(db DatabaseReader, addr common.Address, epoch *big.Int) (*staking.ValidatorSnapshot, error)
- func ReadValidatorStats(db DatabaseReader, addr common.Address) (*staking.ValidatorStats, error)
- func WriteBlock(db DatabaseWriter, block *types.Block) error
- func WriteBlockCommitSig(db DatabaseWriter, blockNum uint64, sigAndBitmap []byte) error
- func WriteBlockRewardAccumulator(db DatabaseWriter, newAccum *big.Int, number uint64) error
- func WriteBlockStxLookUpEntries(db DatabaseWriter, block *types.Block) error
- func WriteBlockTxLookUpEntries(db DatabaseWriter, block *types.Block) error
- func WriteBloomBits(db DatabaseWriter, bit uint, section uint64, head common.Hash, bits []byte) error
- func WriteBody(db DatabaseWriter, hash common.Hash, number uint64, body *types.Body) error
- func WriteBodyRLP(db DatabaseWriter, hash common.Hash, number uint64, rlp rlp.RawValue) error
- func WriteCXReceipts(db DatabaseWriter, shardID uint32, number uint64, hash common.Hash, ...) error
- func WriteCXReceiptsProofSpent(dbw DatabaseWriter, cxp *types.CXReceiptsProof) error
- func WriteCanonicalHash(db DatabaseWriter, hash common.Hash, number uint64) error
- func WriteChainConfig(db DatabaseWriter, hash common.Hash, cfg *params.ChainConfig) error
- func WriteCrossLinkShardBlock(db DatabaseWriter, shardID uint32, blockNum uint64, data []byte) error
- func WriteCxLookupEntries(db DatabaseWriter, block *types.Block) error
- func WriteDatabaseVersion(db DatabaseWriter, version int) error
- func WriteDelegationsByDelegator(db DatabaseWriter, delegator common.Address, indexes staking.DelegationIndexes) error
- func WriteEpochBlockNumber(db DatabaseWriter, epoch, blockNum *big.Int) error
- func WriteEpochVdfBlockNum(db DatabaseWriter, epoch *big.Int, data []byte) error
- func WriteEpochVrfBlockNums(db DatabaseWriter, epoch *big.Int, data []byte) error
- func WriteHeadBlockHash(db DatabaseWriter, hash common.Hash) error
- func WriteHeadFastBlockHash(db DatabaseWriter, hash common.Hash) error
- func WriteHeadHeaderHash(db DatabaseWriter, hash common.Hash) error
- func WriteHeader(db DatabaseWriter, header *block.Header) error
- func WritePendingCrossLinks(db DatabaseWriter, bytes []byte) error
- func WritePendingSlashingCandidates(db DatabaseWriter, bytes []byte) error
- func WritePreimages(db DatabaseWriter, number uint64, preimages map[common.Hash][]byte) error
- func WriteReceipts(db DatabaseWriter, hash common.Hash, number uint64, receipts types.Receipts) error
- func WriteShardLastCrossLink(db DatabaseWriter, shardID uint32, data []byte) error
- func WriteShardStateBytes(db DatabaseWriter, epoch *big.Int, data []byte) error
- func WriteTd(db DatabaseWriter, hash common.Hash, number uint64, td *big.Int) error
- func WriteValidatorList(db DatabaseWriter, addrs []common.Address) error
- func WriteValidatorSnapshot(batch DatabaseWriter, v *staking.ValidatorWrapper, epoch *big.Int) error
- func WriteValidatorStats(batch DatabaseWriter, addr common.Address, stats *staking.ValidatorStats) error
- type DatabaseDeleter
- type DatabaseReader
- type DatabaseWriter
- type TxLookupEntry
Constants ¶
const ( SpentByte byte = iota UnspentByte NAByte // not exist )
Indicate whether the receipts corresponding to a blockHash is spent or not
Variables ¶
var ( // Chain index prefixes (use `i` + single byte to avoid mixing data types). BloomBitsIndexPrefix = []byte("iB") // BloomBitsIndexPrefix is the data table of a chain indexer to track its progress )
The fields below define the low level database schema prefixing.
var MsgNoShardStateFromDB = "failed to read shard state from DB"
MsgNoShardStateFromDB error message for shard state reading failure
Functions ¶
func DeleteBlock ¶
func DeleteBlock(db DatabaseDeleter, hash common.Hash, number uint64) error
DeleteBlock removes all block data associated with a hash.
func DeleteBody ¶
func DeleteBody(db DatabaseDeleter, hash common.Hash, number uint64) error
DeleteBody removes all block body data associated with a hash.
func DeleteCXReceiptsProofSpent ¶
func DeleteCXReceiptsProofSpent(db DatabaseDeleter, shardID uint32, number uint64) error
DeleteCXReceiptsProofSpent removes unspent indicator of a given blockHash
func DeleteCanonicalHash ¶
func DeleteCanonicalHash(db DatabaseDeleter, number uint64) error
DeleteCanonicalHash removes the number to hash canonical mapping.
func DeleteCrossLinkShardBlock ¶
func DeleteCrossLinkShardBlock(db DatabaseDeleter, shardID uint32, blockNum uint64) error
DeleteCrossLinkShardBlock deletes the blockHash given shardID and blockNum
func DeleteCxLookupEntry ¶
func DeleteCxLookupEntry(db DatabaseDeleter, hash common.Hash) error
DeleteCxLookupEntry removes all transaction data associated with a hash.
func DeleteHeader ¶
func DeleteHeader(db DatabaseDeleter, hash common.Hash, number uint64) error
DeleteHeader removes all block header data associated with a hash.
func DeleteReceipts ¶
func DeleteReceipts(db DatabaseDeleter, hash common.Hash, number uint64) error
DeleteReceipts removes all receipt data associated with a block hash.
func DeleteTd ¶
func DeleteTd(db DatabaseDeleter, hash common.Hash, number uint64) error
DeleteTd removes all block total difficulty data associated with a hash.
func DeleteTxLookupEntry ¶
func DeleteTxLookupEntry(db DatabaseDeleter, hash common.Hash) error
DeleteTxLookupEntry removes all transaction data associated with a hash.
func DeleteValidatorSnapshot ¶ added in v1.3.0
DeleteValidatorSnapshot removes the validator's snapshot by its address
func DeleteValidatorStats ¶ added in v1.3.5
func DeleteValidatorStats(db DatabaseDeleter, addr common.Address) error
DeleteValidatorStats ..
func FindCommonAncestor ¶
func FindCommonAncestor(db DatabaseReader, a, b *block.Header) *block.Header
FindCommonAncestor returns the last common ancestor of two block headers
func HasBody ¶
func HasBody(db DatabaseReader, hash common.Hash, number uint64) bool
HasBody verifies the existence of a block body corresponding to the hash.
func HasHeader ¶
func HasHeader(db DatabaseReader, hash common.Hash, number uint64) bool
HasHeader verifies the existence of a block header corresponding to the hash.
func ReadBlock ¶
ReadBlock retrieves an entire block corresponding to the hash, assembling it back from the stored header and body. If either the header or body could not be retrieved nil is returned.
Note, due to concurrent download of header and block body the header and thus canonical hash can be stored in the database but the body data not (yet).
func ReadBlockCommitSig ¶ added in v1.3.8
func ReadBlockCommitSig(db DatabaseReader, blockNum uint64) ([]byte, error)
ReadBlockCommitSig retrieves the signature signed on a block.
func ReadBlockRewardAccumulator ¶ added in v1.3.0
func ReadBlockRewardAccumulator(db DatabaseReader, number uint64) (*big.Int, error)
ReadBlockRewardAccumulator ..
func ReadBloomBits ¶
ReadBloomBits retrieves the compressed bloom bit vector belonging to the given section and bit index from the.
func ReadBodyRLP ¶
ReadBodyRLP retrieves the block body (transactions and uncles) in RLP encoding.
func ReadCXReceipt ¶
func ReadCXReceipt(db DatabaseReader, hash common.Hash) (*types.CXReceipt, common.Hash, uint64, uint64)
ReadCXReceipt retrieves a specific transaction from the database, along with its added positional metadata.
func ReadCXReceipts ¶
func ReadCXReceipts(db DatabaseReader, shardID uint32, number uint64, hash common.Hash) (types.CXReceipts, error)
ReadCXReceipts retrieves all the transactions of receipts given destination shardID, number and blockHash
func ReadCXReceiptsProofSpent ¶
func ReadCXReceiptsProofSpent(db DatabaseReader, shardID uint32, number uint64) (byte, error)
ReadCXReceiptsProofSpent check whether a CXReceiptsProof is unspent
func ReadCanonicalHash ¶
func ReadCanonicalHash(db DatabaseReader, number uint64) common.Hash
ReadCanonicalHash retrieves the hash assigned to a canonical block number.
func ReadChainConfig ¶
func ReadChainConfig(db DatabaseReader, hash common.Hash) *params.ChainConfig
ReadChainConfig retrieves the consensus settings based on the given genesis hash.
func ReadCrossLinkShardBlock ¶
func ReadCrossLinkShardBlock( db DatabaseReader, shardID uint32, blockNum uint64, ) ([]byte, error)
ReadCrossLinkShardBlock retrieves the blockHash given shardID and blockNum
func ReadCxLookupEntry ¶
ReadCxLookupEntry retrieves the positional metadata associated with a transaction hash to allow retrieving cross shard receipt by hash in destination shard not the original transaction in source shard return nil if not found
func ReadDatabaseVersion ¶
func ReadDatabaseVersion(db DatabaseReader) int
ReadDatabaseVersion retrieves the version number of the database.
func ReadDelegationsByDelegator ¶ added in v1.3.0
func ReadDelegationsByDelegator(db DatabaseReader, delegator common.Address) (staking.DelegationIndexes, error)
ReadDelegationsByDelegator retrieves the list of validators delegated by a delegator Returns empty results instead of error if there is not data found.
func ReadEpochBlockNumber ¶
ReadEpochBlockNumber retrieves the epoch block number for the given epoch, or nil if the given epoch is not found in the database.
func ReadEpochVdfBlockNum ¶
func ReadEpochVdfBlockNum(db DatabaseReader, epoch *big.Int) ([]byte, error)
ReadEpochVdfBlockNum retrieves the VDF block number for the given epoch
func ReadEpochVrfBlockNums ¶
func ReadEpochVrfBlockNums(db DatabaseReader, epoch *big.Int) ([]byte, error)
ReadEpochVrfBlockNums retrieves the VRF block numbers for the given epoch
func ReadHeadBlockHash ¶
func ReadHeadBlockHash(db DatabaseReader) common.Hash
ReadHeadBlockHash retrieves the hash of the current canonical head block.
func ReadHeadFastBlockHash ¶
func ReadHeadFastBlockHash(db DatabaseReader) common.Hash
ReadHeadFastBlockHash retrieves the hash of the current fast-sync head block.
func ReadHeadHeaderHash ¶
func ReadHeadHeaderHash(db DatabaseReader) common.Hash
ReadHeadHeaderHash retrieves the hash of the current canonical head header.
func ReadHeader ¶
ReadHeader retrieves the block header corresponding to the hash.
func ReadHeaderNumber ¶
func ReadHeaderNumber(db DatabaseReader, hash common.Hash) *uint64
ReadHeaderNumber returns the header number assigned to a hash.
func ReadHeaderRLP ¶
ReadHeaderRLP retrieves a block header in its raw RLP database encoding.
func ReadPendingCrossLinks ¶ added in v1.3.0
func ReadPendingCrossLinks(db DatabaseReader) ([]byte, error)
ReadPendingCrossLinks retrieves last pending crosslinks.
func ReadPreimage ¶
func ReadPreimage(db DatabaseReader, hash common.Hash) []byte
ReadPreimage retrieves a single preimage of the provided hash.
func ReadReceipt ¶
ReadReceipt retrieves a specific transaction receipt from the database, along with its added positional metadata.
func ReadReceipts ¶
ReadReceipts retrieves all the transaction receipts belonging to a block.
func ReadShardLastCrossLink ¶
func ReadShardLastCrossLink(db DatabaseReader, shardID uint32) ([]byte, error)
ReadShardLastCrossLink read the last cross link of a shard
func ReadShardState ¶
ReadShardState retrieves shard state of a specific epoch.
func ReadStakingTransaction ¶ added in v1.3.0
func ReadStakingTransaction(db DatabaseReader, hash common.Hash) (*staking.StakingTransaction, common.Hash, uint64, uint64)
ReadStakingTransaction retrieves a specific staking transaction from the database, along with its added positional metadata.
func ReadTransaction ¶
func ReadTransaction(db DatabaseReader, hash common.Hash) (*types.Transaction, common.Hash, uint64, uint64)
ReadTransaction retrieves a specific transaction from the database, along with its added positional metadata.
func ReadTxLookupEntry ¶
ReadTxLookupEntry retrieves the positional metadata associated with a transaction hash to allow retrieving the transaction or receipt by hash.
func ReadValidatorList ¶ added in v1.3.0
func ReadValidatorList(db DatabaseReader) ([]common.Address, error)
ReadValidatorList retrieves all staking validators by its address
func ReadValidatorSnapshot ¶ added in v1.3.0
func ReadValidatorSnapshot( db DatabaseReader, addr common.Address, epoch *big.Int, ) (*staking.ValidatorSnapshot, error)
ReadValidatorSnapshot retrieves validator's snapshot by its address
func ReadValidatorStats ¶ added in v1.3.0
func ReadValidatorStats( db DatabaseReader, addr common.Address, ) (*staking.ValidatorStats, error)
ReadValidatorStats retrieves validator's stats by its address,
func WriteBlock ¶
func WriteBlock(db DatabaseWriter, block *types.Block) error
WriteBlock serializes a block into the database, header and body separately.
func WriteBlockCommitSig ¶ added in v1.3.8
func WriteBlockCommitSig(db DatabaseWriter, blockNum uint64, sigAndBitmap []byte) error
WriteBlockCommitSig ..
func WriteBlockRewardAccumulator ¶ added in v1.3.0
func WriteBlockRewardAccumulator(db DatabaseWriter, newAccum *big.Int, number uint64) error
WriteBlockRewardAccumulator ..
func WriteBlockStxLookUpEntries ¶ added in v1.10.0
func WriteBlockStxLookUpEntries(db DatabaseWriter, block *types.Block) error
WriteBlockStxLookUpEntries writes all look up entries of block's staking transactions
func WriteBlockTxLookUpEntries ¶ added in v1.10.0
func WriteBlockTxLookUpEntries(db DatabaseWriter, block *types.Block) error
WriteBlockTxLookUpEntries writes all look up entries of block's transactions
func WriteBloomBits ¶
func WriteBloomBits(db DatabaseWriter, bit uint, section uint64, head common.Hash, bits []byte) error
WriteBloomBits stores the compressed bloom bits vector belonging to the given section and bit index.
func WriteBodyRLP ¶
WriteBodyRLP stores an RLP encoded block body into the database.
func WriteCXReceipts ¶
func WriteCXReceipts(db DatabaseWriter, shardID uint32, number uint64, hash common.Hash, receipts types.CXReceipts) error
WriteCXReceipts stores all the transaction receipts given destination shardID, blockNumber and blockHash
func WriteCXReceiptsProofSpent ¶
func WriteCXReceiptsProofSpent(dbw DatabaseWriter, cxp *types.CXReceiptsProof) error
WriteCXReceiptsProofSpent write CXReceiptsProof as spent into database
func WriteCanonicalHash ¶
func WriteCanonicalHash(db DatabaseWriter, hash common.Hash, number uint64) error
WriteCanonicalHash stores the hash assigned to a canonical block number.
func WriteChainConfig ¶
func WriteChainConfig(db DatabaseWriter, hash common.Hash, cfg *params.ChainConfig) error
WriteChainConfig writes the chain config settings to the database.
func WriteCrossLinkShardBlock ¶
func WriteCrossLinkShardBlock(db DatabaseWriter, shardID uint32, blockNum uint64, data []byte) error
WriteCrossLinkShardBlock stores the blockHash given shardID and blockNum
func WriteCxLookupEntries ¶
func WriteCxLookupEntries(db DatabaseWriter, block *types.Block) error
WriteCxLookupEntries stores a positional metadata for every transaction from a block, enabling hash based transaction and receipt lookups.
func WriteDatabaseVersion ¶
func WriteDatabaseVersion(db DatabaseWriter, version int) error
WriteDatabaseVersion stores the version number of the database
func WriteDelegationsByDelegator ¶ added in v1.3.0
func WriteDelegationsByDelegator(db DatabaseWriter, delegator common.Address, indexes staking.DelegationIndexes) error
WriteDelegationsByDelegator stores the list of validators delegated by a delegator
func WriteEpochBlockNumber ¶
func WriteEpochBlockNumber(db DatabaseWriter, epoch, blockNum *big.Int) error
WriteEpochBlockNumber stores the given epoch-number-to-epoch-block-number in the database.
func WriteEpochVdfBlockNum ¶
func WriteEpochVdfBlockNum(db DatabaseWriter, epoch *big.Int, data []byte) error
WriteEpochVdfBlockNum stores the VDF block number for the given epoch
func WriteEpochVrfBlockNums ¶
func WriteEpochVrfBlockNums(db DatabaseWriter, epoch *big.Int, data []byte) error
WriteEpochVrfBlockNums stores the VRF block numbers for the given epoch
func WriteHeadBlockHash ¶
func WriteHeadBlockHash(db DatabaseWriter, hash common.Hash) error
WriteHeadBlockHash stores the head block's hash.
func WriteHeadFastBlockHash ¶
func WriteHeadFastBlockHash(db DatabaseWriter, hash common.Hash) error
WriteHeadFastBlockHash stores the hash of the current fast-sync head block.
func WriteHeadHeaderHash ¶
func WriteHeadHeaderHash(db DatabaseWriter, hash common.Hash) error
WriteHeadHeaderHash stores the hash of the current canonical head header.
func WriteHeader ¶
func WriteHeader(db DatabaseWriter, header *block.Header) error
WriteHeader stores a block header into the database and also stores the hash- to-number mapping.
func WritePendingCrossLinks ¶ added in v1.3.0
func WritePendingCrossLinks(db DatabaseWriter, bytes []byte) error
WritePendingCrossLinks stores last pending crosslinks into database.
func WritePendingSlashingCandidates ¶ added in v1.3.1
func WritePendingSlashingCandidates(db DatabaseWriter, bytes []byte) error
WritePendingSlashingCandidates stores last pending slashing candidates into database.
func WritePreimages ¶
WritePreimages writes the provided set of preimages to the database. `number` is the current block number, and is used for debug messages only.
func WriteReceipts ¶
func WriteReceipts(db DatabaseWriter, hash common.Hash, number uint64, receipts types.Receipts) error
WriteReceipts stores all the transaction receipts belonging to a block.
func WriteShardLastCrossLink ¶
func WriteShardLastCrossLink(db DatabaseWriter, shardID uint32, data []byte) error
WriteShardLastCrossLink stores the last cross link of a shard
func WriteShardStateBytes ¶
func WriteShardStateBytes(db DatabaseWriter, epoch *big.Int, data []byte) error
WriteShardStateBytes stores sharding state into database.
func WriteValidatorList ¶ added in v1.3.0
func WriteValidatorList( db DatabaseWriter, addrs []common.Address, ) error
WriteValidatorList stores all staking validators by its address
func WriteValidatorSnapshot ¶ added in v1.3.0
func WriteValidatorSnapshot(batch DatabaseWriter, v *staking.ValidatorWrapper, epoch *big.Int) error
WriteValidatorSnapshot stores validator's snapshot by its address
func WriteValidatorStats ¶ added in v1.3.0
func WriteValidatorStats( batch DatabaseWriter, addr common.Address, stats *staking.ValidatorStats, ) error
WriteValidatorStats stores validator's stats by its address
Types ¶
type DatabaseDeleter ¶
DatabaseDeleter wraps the Delete method of a backing data store.
type DatabaseReader ¶
DatabaseReader wraps the Has and Get method of a backing data store.
type DatabaseWriter ¶
DatabaseWriter wraps the Put method of a backing data store.