Storing Data in Ledger

Klave provide access to a Ledger database for your application. The Klave ledger database is tamper-proof NoSQL key-value data-store. This key value store allows Klave developers to persist non-relational data across application invocation in a secure and tamper-proof way. To learn more about the ledger charateristics, check out Ledger and Integrity.

Using the Ledger from Applications

The Klave SDK exposes an interface to interact with the ledger.

The set of operations is the following one:

Class	Operation	Parameters	Returns	Behavior
`Ledger`	`getTable`	name	Table	Return the ledger table with the specified `name`. If no table exists from the `name` provided, then a new table with this name will be automatically created and returned.
`Table`	`get`	key	value	Get the string value associated with the specified `key` from the specified `Table` as string.
`Table`	`set`	key, value	-	Set the `value` as string associated with the specified `key` in the specified `Table`, overwriting any existing value.
`Table`	`unset`	key	-	Delete the tuple with the specified `key` from the specified `Table`.

Storing and deleting data are modifying the state of the App ledger. Therefore, operations like set and unset can be executed only from within a Transactional context.

In AssemblyScipt, the ledger can be accessed through the Ledger keyword. For example:

import { Ledger } from '@klave/sdk';
 
@serializable
export class StoreInput {
    key!: string;
    value!: string;
}
 
/**
 * @transaction
 */
export function storeInLedger(input: StoreInput): void {
    Ledger.getTable("MY_TABLE").set(input.key, input.value);
}
 
/**
 * @query
 */
export function retrieveFromLedger(key: string): void {
    let value = Ledger.getTable("MY_TABLE").get(key);
}

Storing Data in Ledger

Using the Ledger from Applications

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