Icon LinkStoring Info in a Database

The Fuel indexer uses PostgreSQL Icon Link as the primary database.

💡 We're open to supporting other storage solutions in the future.

Icon LinkData Types

Below is a mapping of GraphQL schema types to their Sway and database equivalents. Note that an empty cell denotes that there is no direct equivalent for the type in the corresponding domain.

GraphQL Scalar	Sway Type	Postgres Type
Address	`b256`	varchar(64)
AssetId	`u8[32]`	varchar(64)
Blob	`str[]`	varchar(10485760)
BlockId		varchar(64)
Boolean	`bool`	boolean
Bytes4	`str[4]`	varchar(8)
Bytes8	`str[8]`	varchar(16)
Bytes32	`str[32]`	varchar(64)
Bytes64	`str[64]`	varchar(128)
Charfield	`str[]`	varchar(255)
ContractId	`b256`	varchar(64)
HexString	`str[]`	varchar(10485760)
ID		varchar(64) primary key
Int1	`u8`	integer
Int4	`u32`	integer
Int8	`u64`	bigint
Int16		numeric(39,0)
Json	`str[]`	json
MessageId	`str[32]`	varchar(64)
Nonce	`str[32]`	varchar(64)
Salt	`str[32]`	varchar(64)
Signature	`str[64]`	varchar(128)
Tai64Timestamp		varchar(128)
Timestamp	`u64`	timestamp
UID		varchar(64)
UInt1	`u8`	integer
UInt4	`u32`	integer
UInt8	`u64`	numeric(20, 0)
UInt16		numeric(39, 0)
Virtual		json

Icon LinkExample

Let's define an Event struct in a Sway contract:

struct Event {
    id: u64,
    address: Address,
    block_height: u64,
}

The corresponding GraphQL schema to mirror this Event struct would resemble:

type Event @entity {
    id: ID!
    account: Address!
    block_height: UInt8!
}

And finally, this GraphQL schema will generate the following Postgres schema:

                                           Table "schema.event"
    Column   |     Type    | Collation | Nullable | Default | Storage  | Compression | Stats target | Description
--------------+-------------+-----------+----------+---------+----------+-------------+--------------+-------------
 id           |    bigint   |           | not null |         | plain    |             |              |
 block_height |    bigint   |           | not null |         | plain    |             |              |
 address      | varchar(64) |           | not null |         | plain    |             |              |
 object       |    bytea    |           | not null |         | extended |             |              |
Indexes:
    "event_pkey" PRIMARY KEY, btree (id)
Access method: heap

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