Database Schemas

ELA Main Chain Storage

LevelDB Key Prefixes

Prefix	Purpose
BLK_	Block data storage
TX_	Transaction storage
UTXO_	Unspent transaction outputs
HDR_	Block headers
HGT_	Height-to-hash mapping
FFE_	FFLDB file metadata
SCT_	Small cross-chain transfers
CP_	Checkpoints

FFLDB (Flat File + LevelDB)

The primary storage engine stores full blocks in sequential flat files with LevelDB as the index:

data/
├── mainnet/
│   ├── block/
│   │   ├── blk00000.fdb    # Block data file 0
│   │   ├── blk00001.fdb    # Block data file 1
│   │   └── ...
│   └── index/
│       └── MANIFEST-*      # LevelDB index files
└── checkpoints/
    ├── arbiters_*           # Arbiter state checkpoints
    ├── committee_*          # Elastos Council checkpoints
    └── state_*              # Producer state checkpoints

Block storage format:

[4 bytes: network magic] [4 bytes: block size] [block data]

Each flat file grows up to maxBlockFileSize (512 MB) before rotating.

ChainStore Structure

type ChainStore struct {
    levelDB            IStore            // LevelDB for lightweight lookups
    fflDB              IFFLDBChainStore  // FFLDB for block data
    currentBlockHeight uint32
    persistMutex       sync.Mutex
}

Block Index (In-Memory)

type BlockNode struct {
    Hash       *Uint256
    ParentHash *Uint256
    Height     uint32
    Version    uint32
    Timestamp  uint32
    Bits       uint32
}

The in-memory block index maintains Nodes as a flat array and DepNodes as a dependency map for fork detection.

Arbiter SQLite Schema

Source: store/datastore.go

-- Main chain transaction cache (pending deposits)
CREATE TABLE MainChainTxs (
    TransactionHash TEXT PRIMARY KEY,
    GenesisBlockAddress TEXT,
    TransactionData BLOB,
    MerkleProof BLOB,
    BlockHeight INTEGER
);

-- Sidechain transaction cache (pending withdrawals)
CREATE TABLE SideChainTxs (
    TransactionHash TEXT PRIMARY KEY,
    GenesisBlockAddress TEXT,
    TransactionData BLOB,
    BlockHeight INTEGER
);

-- Finished transactions (succeed/failed tracking)
CREATE TABLE FinishedTxs (
    TransactionHash TEXT PRIMARY KEY,
    GenesisBlockAddress TEXT,
    Status INTEGER,
    BlockHeight INTEGER
);

-- Registered sidechains
CREATE TABLE RegisteredSideChains (
    GenesisBlockAddress TEXT PRIMARY KEY,
    GenesisBlockHash TEXT,
    RegisterHeight INTEGER,
    ExchangeRate REAL,
    EffectiveHeight INTEGER
);

-- Schnorr nonce/R-value cache
CREATE TABLE SchnorrR (
    NonceHash TEXT PRIMARY KEY,
    Rx TEXT,
    Ry TEXT,
    Px TEXT,
    Py TEXT,
    K0 TEXT
);

SPV Storage

Header Store (LevelDB)

Key prefixes in interface/store/prefix.go:

Prefix	Type	Purpose
BKH	[]byte → Header	Block hash → full header data
BKN	uint32 → []byte	Block height → block hash
BST	"best" → []byte	Best (tip) block hash
ARB	uint32 → []byte	Block height → arbiter set

Data Store (LevelDB)

Prefix	Type	Purpose
TXD	txhash → TxData	Transaction data
OPS	outpoint → OpData	Outpoint (UTXO) data
QUE	seq → NotifyData	Pending listener notification queue
ADR	address → bool	Watched addresses
TXT	type → bool	Watched transaction types
CID	id → data	Custom ID reservations

SPV Wallet SQLite (sample app)

CREATE TABLE UTXOs (
    OutPoint BLOB PRIMARY KEY,
    Value INTEGER,
    LockTime INTEGER,
    AtHeight INTEGER
);

CREATE TABLE STXOs (
    OutPoint BLOB PRIMARY KEY,
    Value INTEGER,
    SpendHash BLOB,
    SpendHeight INTEGER
);

CREATE TABLE Txs (
    Hash BLOB PRIMARY KEY,
    RawData BLOB,
    Timestamp INTEGER
);

Hive Node MongoDB Collections

Each user vault has a sandboxed database hive_user_{did_hash}:

Collection	Purpose
auth_register	Registered DID documents for authentication
vault_subscription	Vault subscription records
backup_subscription	Backup subscription records
vault_order	Payment orders
vault_receipt	Payment receipts
scripts	Registered scripting definitions
script_temp_files	Temporary files for script file operations
ipfs_files	File metadata (CID, path, size, timestamps)
ipfs_cid_ref	IPFS CID reference counting
collection_metadata	Collection encryption metadata
User-defined collections	Application data (per-script/per-app)

Carrier v2 Storage

SQLite database for local DHT state:

-- Known nodes for routing table persistence
CREATE TABLE nodes (
    id BLOB PRIMARY KEY,      -- Ed25519 public key (32 bytes)
    address TEXT,              -- IP:port
    last_seen INTEGER,         -- Unix timestamp
    version INTEGER            -- Protocol version
);

-- Stored values (DHT key-value pairs)
CREATE TABLE values (
    key BLOB PRIMARY KEY,     -- SHA-256 hash
    value BLOB,               -- Stored data
    timestamp INTEGER,        -- Creation time
    expiry INTEGER            -- Expiration time
);

-- Peer announcements
CREATE TABLE peers (
    key BLOB,                 -- Lookup key
    peer_id BLOB,             -- Peer's node ID
    address TEXT,             -- Peer's address
    timestamp INTEGER,
    PRIMARY KEY (key, peer_id)
);