docs: improve README.md

README.md

@@ -1,12 +1,130 @@
-# datalayers-adapter-erl
+# Datalayers Adapter for Erlang
 
-A datalayers connector Erlang lib
-=====
+[![Erlang/OTP](https://img.shields.io/badge/Erlang/OTP-27-red.svg)](https://www.erlang.org)
+[![Rust](https://img.shields.io/badge/Rust-1.88-orange.svg)](https://www.rust-lang.org)
 
-An OTP library
+`datalayers-adapter-erl` is an Erlang library for connecting to and interacting with [Datalayers](https://datalayers.cn/) databases. It uses a Rust NIF (Native Implemented Function) for high-performance communication with the Datalayers server via the Arrow Flight SQL protocol.
 
-Build
------
+## Features
+
+- Connect to Datalayers with or without TLS.
+- Execute SQL queries.
+- Use prepared statements for optimized query execution.
+- Asynchronous APIs for non-blocking operations.
+- Automatic type conversion between Erlang terms and Datalayers types.
+
+## Building
+
+To build the library, you need to have `rebar3` and the Rust toolchain installed.
+
+```bash
+$ rebar3 compile
+```
+
+## Usage
+
+### Add as a Dependency
+
+Add the following to your `rebar.config` file:
+
+```erlang
+{deps, [
+    {datalayers, {git, "https://github.com/datalayers-io/datalayers-adapter-erl.git", {tag, "0.1.0"}}}
+]}.
+```
+
+### Connecting to Datalayers
+
+To connect to a Datalayers instance, use the `datalayers:connect/1` function with a map of options.
+
+**Without TLS:**
+
+```erlang
+Opts = #{
+    host => <<"localhost">>,
+    port => 8360,
+    username => <<"admin">>,
+    password => <<"public">>
+},
+{ok, Client} = datalayers:connect(Opts).
+```
+
+**With TLS:**
+
+```erlang
+Opts = #{
+    host => <<"localhost">>,
+    port => 8360,
+    username => <<"admin">>,
+    password => <<"public">>,
+    tls_cert => <<"/path/to/ca.crt">>
+},
+{ok, Client} = datalayers:connect(Opts).
+```
+
+### Executing Queries
+
+Use `datalayers:execute/2` to run SQL queries.
+
+```erlang
+{ok, Client} = datalayers:connect(Opts),
+{ok, Result} = datalayers:execute(Client, <<"SELECT version()">>).
+%% Result will be [[<<"2.3.8">>]]
+```
+
+### Using a Specific Database
+
+After connecting, you can switch to a specific database using `datalayers:use_database/2`.
+
+```erlang
+ok = datalayers:use_database(Client, <<"my_database">>).
+```
+
+### Prepared Statements
+
+For queries that are executed multiple times, prepared statements can improve performance.
+
+```erlang
+{ok, Client} = datalayers:connect(Opts),
+ok = datalayers:use_database(Client, <<"my_database">>),
+
+Sql = <<"INSERT INTO my_table (ts, sid, value, flag) VALUES (?, ?, ?, ?)">>,
+{ok, PreparedStatement} = datalayers:prepare(Client, Sql),
+
+Timestamp = erlang:system_time(millisecond),
+Params = [
+    [Timestamp, 1, 42.0, 1],
+    [Timestamp, 2, 43.0, 0]
+],
+{ok, _} = datalayers:execute_prepare(Client, PreparedStatement, Params),
+
+ok = datalayers:close_prepared(Client, PreparedStatement).
+```
+
+### Asynchronous Operations
+
+The library also provides asynchronous versions of `execute`, `prepare`, and `execute_prepare`. These functions take a callback function that will be executed with the result.
+
+```erlang
+Callback = {fun(Result) -> io:format("Result: ~p~n", [Result]) end, []},
+ok = datalayers:async_execute(Client, <<"SELECT * FROM my_table">>, Callback).
 ```
-    $ rebar3 compile
+
+### Stopping the Client
+
+To close the connection and clean up resources, use `datalayers:stop/1`.
+
+```erlang
+ok = datalayers:stop(Client).
+```
+
+## Running Tests
+
+To run the test suite, use `rebar3 eunit`. The tests require a running Datalayers instance. You can configure the connection details using environment variables:
+
+-   `DATALAYERS_TCP_ADDR`: The address for TCP tests (defaults to `localhost`).
+-   `DATALAYERS_TLS_ADDR`: The address for TLS tests (defaults to `localhost`).
+
+```bash
+$ rebar3 eunit
 ```