diff --git a/src/_test/__snapshots__/index.test.ts.snapshot b/src/_test/__snapshots__/index.test.ts.snapshot
new file mode 100644
index 0000000..fa81d10
--- /dev/null
+++ b/src/_test/__snapshots__/index.test.ts.snapshot
@@ -0,0 +1,608 @@
+exports[`typegen > generate types matching snapshot 1`] = `
+{
+  "lines": [
+    "// This file was automatically generated by \`kysely-typegen\`.",
+    "// Do not edit this file manually.",
+    "",
+    "import type { ColumnType } from \\"kysely\\"",
+    "",
+    "export type Generated<T> = T extends ColumnType<infer S, infer I, infer U> ? ColumnType<S, I | undefined, U> : ColumnType<T, T | undefined, T>",
+    "",
+    "export type Timestamp = ColumnType<Date, Date | string, Date | string>",
+    "",
+    "export type Numeric = ColumnType<string, number | string, number | string>",
+    "",
+    "export type Int8 = ColumnType<string, bigint | number | string, bigint | number | string>",
+    "",
+    "export type Json = JsonValue",
+    "",
+    "export type JsonArray = JsonValue[]",
+    "",
+    "export interface JsonObject {",
+    "  [x: string]: JsonValue | undefined",
+    "}",
+    "",
+    "export type JsonPrimitive = boolean | number | string | null",
+    "",
+    "export type JsonValue = JsonArray | JsonObject | JsonPrimitive",
+    "",
+    "export type Currency = \\"EUR\\" | \\"GBP\\" | \\"USD\\"",
+    "",
+    "export type OrderStatus = \\"cancelled\\" | \\"paid\\" | \\"pending\\" | \\"shipped\\"",
+    "",
+    "export type UserRole = \\"admin\\" | \\"guest\\" | \\"member\\"",
+    "",
+    "export interface AllTypes {",
+    "  colBit: string",
+    "  colBool: boolean",
+    "  colBoolDefault: Generated<boolean>",
+    "  colBoolNullable: boolean | null",
+    "  colBox: string",
+    "  colBpchar: string",
+    "  colBytea: Buffer",
+    "  colCidr: string",
+    "  colDate: Timestamp",
+    "  colFloat4: number",
+    "  colFloat8: number",
+    "  colInet: string",
+    "  colInt2: number",
+    "  colInt4: number",
+    "  colInt8: Int8",
+    "  colJson: Json",
+    "  colJsonb: Json",
+    "  colJsonbDefault: Generated<Json>",
+    "  colLine: string",
+    "  colLseg: string",
+    "  colMacaddr: string",
+    "  colMoney: string",
+    "  colNumeric: Numeric",
+    "  colOid: number",
+    "  colPath: string",
+    "  colPoint: unknown",
+    "  colPolygon: string",
+    "  colText: string",
+    "  colTextNullable: string | null",
+    "  colTime: string",
+    "  colTimestamp: Timestamp",
+    "  colTimestampDefault: Generated<Timestamp>",
+    "  colTimestamptz: Timestamp",
+    "  colTimetz: string",
+    "  colTsquery: string",
+    "  colTsvector: string",
+    "  colUuid: string",
+    "  colVarbit: string",
+    "  colVarchar: string",
+    "  colXml: string",
+    "  createdAt: Generated<Timestamp>",
+    "  id: Generated<string>",
+    "  updatedAt: Timestamp | null",
+    "}",
+    "",
+    "export interface Orders {",
+    "  amountCents: number",
+    "  createdAt: Generated<Timestamp>",
+    "  currency: Generated<Currency>",
+    "  id: Generated<Int8>",
+    "  note: string | null",
+    "  status: Generated<OrderStatus>",
+    "  userId: string",
+    "}",
+    "",
+    "export interface Users {",
+    "  createdAt: Generated<Timestamp>",
+    "  email: string | null",
+    "  id: Generated<string>",
+    "  isActive: Generated<boolean>",
+    "  role: Generated<UserRole>",
+    "  username: string",
+    "}",
+    "",
+    "export interface DB {",
+    "  AllTypes: AllTypes",
+    "  Orders: Orders",
+    "  Users: Users",
+    "}"
+  ],
+  "enums": [
+    {
+      "name": "Currency",
+      "values": [
+        "EUR",
+        "GBP",
+        "USD"
+      ]
+    },
+    {
+      "name": "OrderStatus",
+      "values": [
+        "cancelled",
+        "paid",
+        "pending",
+        "shipped"
+      ]
+    },
+    {
+      "name": "UserRole",
+      "values": [
+        "admin",
+        "guest",
+        "member"
+      ]
+    }
+  ],
+  "tables": [
+    {
+      "columns": [
+        {
+          "dataType": "uuid",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": true,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "id"
+        },
+        {
+          "dataType": "bool",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colBool"
+        },
+        {
+          "dataType": "bool",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": true,
+          "name": "colBoolNullable"
+        },
+        {
+          "dataType": "bool",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": true,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colBoolDefault"
+        },
+        {
+          "dataType": "int2",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colInt2"
+        },
+        {
+          "dataType": "int4",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colInt4"
+        },
+        {
+          "dataType": "int8",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colInt8"
+        },
+        {
+          "dataType": "float4",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colFloat4"
+        },
+        {
+          "dataType": "float8",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colFloat8"
+        },
+        {
+          "dataType": "numeric",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colNumeric"
+        },
+        {
+          "dataType": "money",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colMoney"
+        },
+        {
+          "dataType": "text",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colText"
+        },
+        {
+          "dataType": "varchar",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colVarchar"
+        },
+        {
+          "dataType": "bpchar",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colBpchar"
+        },
+        {
+          "dataType": "bytea",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colBytea"
+        },
+        {
+          "dataType": "date",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colDate"
+        },
+        {
+          "dataType": "time",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colTime"
+        },
+        {
+          "dataType": "timetz",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colTimetz"
+        },
+        {
+          "dataType": "timestamp",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colTimestamp"
+        },
+        {
+          "dataType": "timestamptz",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colTimestamptz"
+        },
+        {
+          "dataType": "json",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colJson"
+        },
+        {
+          "dataType": "jsonb",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colJsonb"
+        },
+        {
+          "dataType": "uuid",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colUuid"
+        },
+        {
+          "dataType": "inet",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colInet"
+        },
+        {
+          "dataType": "cidr",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colCidr"
+        },
+        {
+          "dataType": "macaddr",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colMacaddr"
+        },
+        {
+          "dataType": "bit",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colBit"
+        },
+        {
+          "dataType": "varbit",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colVarbit"
+        },
+        {
+          "dataType": "xml",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colXml"
+        },
+        {
+          "dataType": "tsvector",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colTsvector"
+        },
+        {
+          "dataType": "tsquery",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colTsquery"
+        },
+        {
+          "dataType": "point",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colPoint"
+        },
+        {
+          "dataType": "line",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colLine"
+        },
+        {
+          "dataType": "lseg",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colLseg"
+        },
+        {
+          "dataType": "box",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colBox"
+        },
+        {
+          "dataType": "path",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colPath"
+        },
+        {
+          "dataType": "polygon",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colPolygon"
+        },
+        {
+          "dataType": "oid",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colOid"
+        },
+        {
+          "dataType": "text",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": true,
+          "name": "colTextNullable"
+        },
+        {
+          "dataType": "jsonb",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": true,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colJsonbDefault"
+        },
+        {
+          "dataType": "timestamp",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": true,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "colTimestampDefault"
+        },
+        {
+          "dataType": "timestamptz",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": true,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "createdAt"
+        },
+        {
+          "dataType": "timestamptz",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": true,
+          "name": "updatedAt"
+        }
+      ],
+      "isForeign": false,
+      "isView": false,
+      "name": "AllTypes",
+      "schema": "public"
+    },
+    {
+      "columns": [
+        {
+          "dataType": "int8",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": true,
+          "isAutoIncrementing": true,
+          "isNullable": false,
+          "name": "id"
+        },
+        {
+          "dataType": "uuid",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "userId"
+        },
+        {
+          "dataType": "OrderStatus",
+          "dataTypeSchema": "public",
+          "hasDefaultValue": true,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "status"
+        },
+        {
+          "dataType": "Currency",
+          "dataTypeSchema": "public",
+          "hasDefaultValue": true,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "currency"
+        },
+        {
+          "dataType": "int4",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "amountCents"
+        },
+        {
+          "dataType": "text",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": true,
+          "name": "note"
+        },
+        {
+          "dataType": "timestamptz",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": true,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "createdAt"
+        }
+      ],
+      "isForeign": false,
+      "isView": false,
+      "name": "Orders",
+      "schema": "public"
+    },
+    {
+      "columns": [
+        {
+          "dataType": "uuid",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": true,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "id"
+        },
+        {
+          "dataType": "varchar",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "username"
+        },
+        {
+          "dataType": "text",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": false,
+          "isAutoIncrementing": false,
+          "isNullable": true,
+          "name": "email"
+        },
+        {
+          "dataType": "UserRole",
+          "dataTypeSchema": "public",
+          "hasDefaultValue": true,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "role"
+        },
+        {
+          "dataType": "bool",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": true,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "isActive"
+        },
+        {
+          "dataType": "timestamptz",
+          "dataTypeSchema": "pg_catalog",
+          "hasDefaultValue": true,
+          "isAutoIncrementing": false,
+          "isNullable": false,
+          "name": "createdAt"
+        }
+      ],
+      "isForeign": false,
+      "isView": false,
+      "name": "Users",
+      "schema": "public"
+    }
+  ]
+}
+`;
diff --git a/src/_test/index.test.ts b/src/_test/index.test.ts
index aa246fb..735995f 100644
--- a/src/_test/index.test.ts
+++ b/src/_test/index.test.ts
@@ -1,17 +1,242 @@
-import assert from "node:assert/strict"
-import { describe, it } from "node:test"
-import { fn } from "../index.ts"
+import type { StartedPostgreSqlContainer } from "@testcontainers/postgresql"
+import { PostgreSqlContainer } from "@testcontainers/postgresql"
+import { Kysely, sql } from "kysely"
+import { PostgresJSDialect } from "kysely-postgres-js"
+import path from "node:path"
+import { after, before, describe, it, snapshot } from "node:test"
+import postgres from "postgres"
+import { KyselyTypegenPostgresDialect } from "../index.ts"
 
-describe("index", () => {
-  it('should return "Hello, tsdown!"', () => {
+snapshot.setResolveSnapshotPath((testFilePath) => {
+  if (testFilePath == null) {
+    throw new Error('"testFilePath" is null.')
+  }
+  const dir = path.dirname(testFilePath)
+  const base = path.basename(testFilePath)
+  return path.join(dir, "__snapshots__", `${base}.snapshot`)
+})
+
+const POSTGRES_IMAGE =
+  "docker.io/postgres:18.4@sha256:f7ce845ee6873dd84be93c9828fe0d1fab0f9707dc9ac569694657398b290bce"
+
+const createSchema = async (database: Kysely<any>): Promise<void> => {
+  await database.schema.createType("Currency").asEnum(["EUR", "USD", "GBP"]).execute()
+  await database.schema.createType("UserRole").asEnum(["admin", "member", "guest"]).execute()
+  await database.schema
+    .createType("OrderStatus")
+    .asEnum(["pending", "paid", "shipped", "cancelled"])
+    .execute()
+
+  await database.schema
+    .createTable("AllTypes")
+    .addColumn("id", "uuid", (column) => {
+      return column
+        .notNull()
+        .primaryKey()
+        .defaultTo(sql`gen_random_uuid()`)
+    })
+    .addColumn("colBool", "boolean", (column) => {
+      return column.notNull()
+    })
+    .addColumn("colBoolNullable", "boolean")
+    .addColumn("colBoolDefault", "boolean", (column) => {
+      return column.notNull().defaultTo(false)
+    })
+    .addColumn("colInt2", "smallint", (column) => {
+      return column.notNull()
+    })
+    .addColumn("colInt4", "integer", (column) => {
+      return column.notNull()
+    })
+    .addColumn("colInt8", "bigint", (column) => {
+      return column.notNull()
+    })
+    .addColumn("colFloat4", "real", (column) => {
+      return column.notNull()
+    })
+    .addColumn("colFloat8", "double precision", (column) => {
+      return column.notNull()
+    })
+    .addColumn("colNumeric", sql`numeric(12, 2)`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colMoney", sql`money`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colText", "text", (column) => {
+      return column.notNull()
+    })
+    .addColumn("colVarchar", "varchar(255)", (column) => {
+      return column.notNull()
+    })
+    .addColumn("colBpchar", sql`char(10)`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colBytea", "bytea", (column) => {
+      return column.notNull()
+    })
+    .addColumn("colDate", "date", (column) => {
+      return column.notNull()
+    })
+    .addColumn("colTime", "time", (column) => {
+      return column.notNull()
+    })
+    .addColumn("colTimetz", sql`timetz`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colTimestamp", "timestamp", (column) => {
+      return column.notNull()
+    })
+    .addColumn("colTimestamptz", "timestamptz", (column) => {
+      return column.notNull()
+    })
+    .addColumn("colJson", "json", (column) => {
+      return column.notNull()
+    })
+    .addColumn("colJsonb", "jsonb", (column) => {
+      return column.notNull()
+    })
+    .addColumn("colUuid", "uuid", (column) => {
+      return column.notNull()
+    })
+    .addColumn("colInet", sql`inet`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colCidr", sql`cidr`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colMacaddr", sql`macaddr`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colBit", sql`bit(8)`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colVarbit", sql`varbit(16)`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colXml", sql`xml`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colTsvector", sql`tsvector`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colTsquery", sql`tsquery`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colPoint", sql`point`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colLine", sql`line`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colLseg", sql`lseg`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colBox", sql`box`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colPath", sql`path`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colPolygon", sql`polygon`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colOid", sql`oid`, (column) => {
+      return column.notNull()
+    })
+    .addColumn("colTextNullable", "text")
+    .addColumn("colJsonbDefault", "jsonb", (column) => {
+      return column.notNull().defaultTo(sql`'{}'::jsonb`)
+    })
+    .addColumn("colTimestampDefault", "timestamp", (column) => {
+      return column.notNull().defaultTo(sql`now()`)
+    })
+    .addColumn("createdAt", "timestamptz", (column) => {
+      return column.notNull().defaultTo(sql`now()`)
+    })
+    .addColumn("updatedAt", "timestamptz")
+    .execute()
+
+  await database.schema
+    .createTable("Users")
+    .addColumn("id", "uuid", (column) => {
+      return column
+        .notNull()
+        .primaryKey()
+        .defaultTo(sql`gen_random_uuid()`)
+    })
+    .addColumn("username", "varchar(50)", (column) => {
+      return column.notNull().unique()
+    })
+    .addColumn("email", "text")
+    .addColumn("role", sql`"UserRole"`, (column) => {
+      return column.notNull().defaultTo("member")
+    })
+    .addColumn("isActive", "boolean", (column) => {
+      return column.notNull().defaultTo(true)
+    })
+    .addColumn("createdAt", "timestamptz", (column) => {
+      return column.notNull().defaultTo(sql`now()`)
+    })
+    .execute()
+
+  await database.schema
+    .createTable("Orders")
+    .addColumn("id", "bigserial", (column) => {
+      return column.notNull().primaryKey()
+    })
+    .addColumn("userId", "uuid", (column) => {
+      return column.notNull().references("Users.id")
+    })
+    .addColumn("status", sql`"OrderStatus"`, (column) => {
+      return column.notNull().defaultTo("pending")
+    })
+    .addColumn("currency", sql`"Currency"`, (column) => {
+      return column.notNull().defaultTo("EUR")
+    })
+    .addColumn("amountCents", "integer", (column) => {
+      return column.notNull()
+    })
+    .addColumn("note", "text")
+    .addColumn("createdAt", "timestamptz", (column) => {
+      return column.notNull().defaultTo(sql`now()`)
+    })
+    .execute()
+}
+
+describe("typegen", () => {
+  let container: StartedPostgreSqlContainer
+  let database: Kysely<any>
+
+  before(async () => {
+    container = await new PostgreSqlContainer(POSTGRES_IMAGE).start()
+    database = new Kysely<any>({
+      dialect: new PostgresJSDialect({
+        postgres: postgres({
+          database: container.getDatabase(),
+          host: container.getHost(),
+          port: container.getPort(),
+          user: container.getUsername(),
+          password: container.getPassword(),
+        }),
+      }),
+    })
+    await createSchema(database)
+  })
+
+  after(async () => {
+    await database.destroy()
+    await container.stop()
+  })
+
+  it("generate types matching snapshot", async (testContext) => {
     // Arrange - Given
-    const input = "tsdown"
+    const databaseTypegen = new KyselyTypegenPostgresDialect({ database })
 
     // Act - When
-    const output = fn(input)
+    const result = await databaseTypegen.typegen()
 
     // Assert - Then
-    const expected = "Hello, tsdown!"
-    assert.strictEqual(output, expected)
+    testContext.assert.snapshot(result)
   })
 })
diff --git a/src/index.ts b/src/index.ts
index fae4df4..8721ca0 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,3 +1,191 @@
-export const fn = (input: string): string => {
-  return `Hello, ${input}!`
+import type { Kysely, TableMetadata as KyselyTableMetadata } from "kysely"
+
+export type TableMetadata = KyselyTableMetadata
+export interface EnumMetadata {
+  name: string
+  values: string[]
+}
+
+export abstract class KyselyTypegenDialect {
+  public abstract readonly database: Kysely<any>
+  public abstract readonly scalars: Record<string, string>
+
+  public async getTables(): Promise<TableMetadata[]> {
+    const tables = await this.database.introspection.getTables()
+    return tables.sort((a, b) => {
+      return a.name.localeCompare(b.name)
+    })
+  }
+  public getTablesTypegen(tables: TableMetadata[], enums: EnumMetadata[]): string[] {
+    const enumNames = new Set(
+      enums.map((enumMetadata) => {
+        return enumMetadata.name
+      }),
+    )
+    const result: string[] = []
+    for (const table of tables) {
+      const interfaceName = table.name
+      result.push(`export interface ${interfaceName} {`)
+      const columns = [...table.columns].sort((a, b) => {
+        return a.name.localeCompare(b.name)
+      })
+      for (const column of columns) {
+        const isEnum = enumNames.has(column.dataType)
+        const baseType = isEnum ? column.dataType : (this.scalars[column.dataType] ?? "unknown")
+        let columnType = column.isNullable ? `${baseType} | null` : baseType
+        if (column.hasDefaultValue || column.isAutoIncrementing) {
+          columnType = `Generated<${columnType}>`
+        }
+        result.push(`  ${column.name}: ${columnType}`)
+      }
+      result.push("}", "")
+    }
+    return result
+  }
+
+  protected abstract getEnumsMap(): Promise<Map<string, string[]>>
+  public async getEnums(): Promise<EnumMetadata[]> {
+    const enumsMap = await this.getEnumsMap()
+    const enums: EnumMetadata[] = []
+    for (const [name, values] of enumsMap) {
+      enums.push({ name, values })
+    }
+    return enums.sort((a, b) => {
+      return a.name.localeCompare(b.name)
+    })
+  }
+  public getEnumsTypegen(enums: EnumMetadata[]): string[] {
+    const result: string[] = []
+    for (const enumMetadata of enums) {
+      const enumName = enumMetadata.name
+      result.push(
+        `export type ${enumName} = ${enumMetadata.values
+          .map((value) => {
+            return `"${value}"`
+          })
+          .join(" | ")}`,
+        "",
+      )
+    }
+    return result
+  }
+
+  public abstract typegen(): Promise<{
+    lines: string[]
+    enums: EnumMetadata[]
+    tables: TableMetadata[]
+  }>
+}
+export class KyselyTypegenPostgresDialect extends KyselyTypegenDialect {
+  public database: KyselyTypegenDialect["database"]
+
+  // These types have been found through experimentation in Adminer and in the 'pg' source code.
+  public readonly scalars: Record<string, string> = {
+    bit: "string",
+    bool: "boolean",
+    box: "string",
+    bpchar: "string",
+    bytea: "Buffer",
+    cidr: "string",
+    date: "Timestamp",
+    float4: "number",
+    float8: "number",
+    inet: "string",
+    int2: "number",
+    int4: "number",
+    int8: "Int8",
+    json: "Json",
+    jsonb: "Json",
+    line: "string",
+    lseg: "string",
+    macaddr: "string",
+    money: "string",
+    numeric: "Numeric",
+    oid: "number",
+    path: "string",
+    polygon: "string",
+    text: "string",
+    time: "string",
+    timestamp: "Timestamp",
+    timestamptz: "Timestamp",
+    timetz: "string",
+    tsquery: "string",
+    tsvector: "string",
+    uuid: "string",
+    varbit: "string",
+    varchar: "string",
+    xml: "string",
+  }
+
+  public constructor(input: { database: KyselyTypegenDialect["database"] }) {
+    super()
+    this.database = input.database
+  }
+
+  protected async getEnumsMap(): Promise<Map<string, string[]>> {
+    const rows = await this.database
+      .withoutPlugins()
+      .selectFrom("pg_type as type")
+      .innerJoin("pg_enum as enum", "type.oid", "enum.enumtypid")
+      .innerJoin("pg_catalog.pg_namespace as namespace", "namespace.oid", "type.typnamespace")
+      .select(["type.typname as enumName", "enum.enumlabel as enumValue"])
+      .execute()
+    const enums = new Map<string, string[]>()
+    for (const row of rows) {
+      const data = row as { enumName: string; enumValue: string }
+      enums.set(
+        data.enumName,
+        [...(enums.get(data.enumName) ?? []), data.enumValue].sort((a, b) => {
+          return a.localeCompare(b)
+        }),
+      )
+    }
+    return enums
+  }
+
+  /**
+   * Generate TypeScript types based on the database schema, including tables and enums.
+   */
+  public async typegen(): Promise<{
+    lines: string[]
+    enums: EnumMetadata[]
+    tables: TableMetadata[]
+  }> {
+    const [tables, enums] = await Promise.all([this.getTables(), this.getEnums()])
+    const lines: string[] = [
+      `// This file was automatically generated by \`kysely-typegen\`.`,
+      "// Do not edit this file manually.",
+      "",
+      'import type { ColumnType } from "kysely"',
+      "",
+      "export type Generated<T> = T extends ColumnType<infer S, infer I, infer U> ? ColumnType<S, I | undefined, U> : ColumnType<T, T | undefined, T>",
+      "",
+      "export type Timestamp = ColumnType<Date, Date | string, Date | string>",
+      "",
+      "export type Numeric = ColumnType<string, number | string, number | string>",
+      "",
+      "export type Int8 = ColumnType<string, bigint | number | string, bigint | number | string>",
+      "",
+      "export type Json = JsonValue",
+      "",
+      "export type JsonArray = JsonValue[]",
+      "",
+      "export interface JsonObject {",
+      "  [x: string]: JsonValue | undefined",
+      "}",
+      "",
+      "export type JsonPrimitive = boolean | number | string | null",
+      "",
+      "export type JsonValue = JsonArray | JsonObject | JsonPrimitive",
+      "",
+    ]
+    lines.push(...this.getEnumsTypegen(enums))
+    lines.push(...this.getTablesTypegen(tables, enums))
+    lines.push("export interface DB {")
+    for (const table of tables) {
+      lines.push(`  ${table.name}: ${table.name}`)
+    }
+    lines.push("}")
+    return { lines, enums, tables }
+  }
 }