The Neighborhood streams decoded onchain data directly to your database. Once you’ve tested your transformation, the next step is preparing the right table to receive incoming data. To get a real example of your pipeline’s output use the Test Transformation API to run a dry-run and view the event format. Here’s an example output from a tested transformation: 
[
  {
    "chain": "ETHEREUM",
    "block": 22282149,
    "transaction_hash": "0xc0814c035946d6889497a82d6515647f939f1dfe5d86d46c4294b3c6b127bad7",
    "log_index": 534,
    "contract_address": "0x87870bca3f3fd6335c3f4ce8392d69350b4fa4e2",
    "decoded": {
      "reserve": "0xD533a949740bb3306d119CC777fa900bA034cd52",
      "onBehalfOf": "0x3f3B17da678a495EbEc8a061657Cb6CFa4901531",
      "referralCode": 0,
      "user": "0x3f3B17da678a495EbEc8a061657Cb6CFa4901531",
      "amount": "15000000000000000000000"
    },
    "event_name": "Supply"
  }
]
Alternatively, paste your transformation code into an large language model (LLM) like ChatGPT and ask it to generate a table based on this code. The model will make assumptions on the data, so ensure to check the generated table schema.

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Step 1: Generate a Table Schema

Paste the example output into an LLM or a tool like jsonschema2ddl, and ask it to generate a CREATE TABLE statement for your database of choice (e.g., PostgreSQL, MySQL, SQLite). The primary key has to be a unique combination. Example prompt: 
Convert this JSON into a CREATE TABLE statement for [your database type].
Use appropriate types (e.g., bigint, text, jsonb). Name the table [your table name].
Add a compound primary key on (chain, transaction_hash, log_index).

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Step 2: Run the Table Schema in Your Database

Here’s an ideal result if you’re using PostgreSQL: 
CREATE TABLE AavePool (
  chain TEXT NOT NULL,
  block BIGINT NOT NULL,
  transaction_hash TEXT NOT NULL,
  log_index INTEGER NOT NULL,
  contract_address TEXT NOT NULL,
  event_name TEXT NOT NULL,
  decoded JSONB NOT NULL,
  created_at TIMESTAMPTZ DEFAULT now(),
  PRIMARY KEY (chain, transaction_hash, log_index)
);
This schema uses a compound key to ensure idempotency. Since pipelines provide at-least-once delivery, uniqueness matters to prevent duplicate rows and ensure data integrity.

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Need Help?

Need help setting this up? Send us your sample output at hello@indexing.co — we’ll help generate or review the schema for you.