sql ddl compatibility derived

{
  "input": {
    "body": {
      "role": "both",
      "after": "CREATE TABLE customers (\n  id        bigint       NOT NULL PRIMARY KEY,\n  email     varchar(255) NOT NULL UNIQUE,\n  region    varchar(2)\n);\n\nCREATE TABLE orders (\n  id           bigint        NOT NULL PRIMARY KEY,\n  customer_id  bigint        NOT NULL REFERENCES customers(id),\n  total        numeric(12,2) NOT NULL,\n  status       varchar(20)   NOT NULL,\n  currency     char(3)       NOT NULL,\n  placed_at    timestamp with time zone NOT NULL,\n  CONSTRAINT orders_customer_status_uq UNIQUE (customer_id, status)\n);",
      "before": "CREATE TABLE customers (\n  id        integer      NOT NULL PRIMARY KEY,\n  email     varchar(255) NOT NULL UNIQUE,\n  region    varchar(2)\n);\n\nCREATE TABLE orders (\n  id           integer       NOT NULL PRIMARY KEY,\n  customer_id  integer       NOT NULL REFERENCES customers(id),\n  total        numeric(12,2) NOT NULL DEFAULT 0,\n  status       varchar(20),\n  internal_ref text,\n  placed_at    timestamp with time zone NOT NULL\n);"
    },
    "type": "http",
    "method": "POST",
    "bodyType": "json"
  },
  "output": {
    "type": "json",
    "example": {
      "role": "both",
      "limits": {
        "maxTables": 400,
        "maxDdlBytes": 262144,
        "maxFindings": 500,
        "maxStatements": 2000,
        "maxColumnsPerTable": 500
      },
      "passed": false,
      "complete": true,
      "findings": [
        {
          "code": "COLUMN_TYPE_WIDENED",
          "table": "customers",
          "breaks": [
            "readers"
          ],
          "column": "id",
          "detail": "customers.id widens from integer to bigint. The database accepts this, but a client that decoded the old type can overflow on a value the new one permits."
        },
        {
          "code": "COLUMN_TYPE_WIDENED",
          "table": "orders",
          "breaks": [
            "readers"
          ],
          "column": "id",
          "detail": "orders.id widens from integer to bigint. The database accepts this, but a client that decoded the old type can overflow on a value the new one permits."
        },
        {
          "code": "COLUMN_TYPE_WIDENED",
          "table": "orders",
          "breaks": [
            "readers"
          ],
          "column": "customer_id",
          "detail": "orders.customer_id widens from integer to bigint. The database accepts this, but a client that decoded the old type can overflow on a value the new one permits."
        }
      ],
      "compatible": false,
      "request_id": "example-request",
      "service_id": "sql_ddl_compatibility",
      "assumptions": [
        "A PRIMARY KEY column is treated as NOT NULL whether or not it says so, because the server enforces that.",
        "Widening inside one type family is reported for readers and not for writers: the database accepts the wider value, and the client that decoded the narrower type is the thing that overflows.",
        "A change crossing type families is reported as breaking for both, since neither the stored values nor the client binding carries across."
      ],
      "limitations": [
        "Only the declared schema is read. No database is contacted and no rows are seen, so nothing here reports whether a migration will succeed against the data actually present.",
        "DDL is read as a documented subset: CREATE TABLE, ALTER TABLE, CREATE and DROP INDEX, DROP TABLE, TRUNCATE, GRANT and REVOKE. Anything else — a view, function, trigger or data statement — is listed in...",
        "A renamed column is reported as one removed and one added, because a declaration cannot distinguish a rename from an unrelated pair without the migration that performed it. sql_migration_blast_radius ..."
      ],
      "observed_at": "2026-10-02T00:00:00.000Z",
      "not_examined": [],
      "tables_added": [],
      "tables_after": 2,
      "finding_count": 8,
      "tables_before": 2,
      "breaking_count": 8,
      "service_version": "1.0.0",
      "tables_compared": 2,
      "columns_compared": 8,
      "findings_by_code": {
        "COLUMN_REMOVED": 1,
        "COLUMN_TYPE_WIDENED": 3,
        "REQUIRED_COLUMN_ADDED": 1,
        "COLUMN_BECAME_NOT_NULL": 1,
        "COLUMN_DEFAULT_REMOVED": 1,
        "UNIQUE_CONSTRAINT_ADDED": 1
      }
    }
  }
}