# 慧添翼考试

## 启动数据库

```bash
$ pg_ctl -D /usr/local/var/postgres start
```

## 创建数据库

```bash
$ psql postgres
postgres=# create database htyws owner hty encoding utf8;
CREATE DATABASE
postgres=# \q
```

## 创建用户

```bash
postgres=# create user hty;
CREATE ROLE
```

## 改变数据库owner

```bash
postgres=# alter database htyws owner to hty;
ALTER DATABASE
postgres=#
```

## 改变tables的owner

```bash
htyws=# \dt
                  List of relations
 Schema |            Name            | Type  | Owner 
--------+----------------------------+-------+-------
 public | __diesel_schema_migrations | table | htyws
 public | rewards                    | table | weli
 public | users                      | table | weli
(3 rows)
```

```bash
htyws=# alter table __diesel_schema_migrations owner to htyws;
ALTER TABLE
htyws=# alter table rewards owner to htyws;
ALTER TABLE
htyws=# alter table users owner to htyws;
ALTER TABLE
```

```bash
htyws=# \dt
                  List of relations
 Schema |            Name            | Type  | Owner 
--------+----------------------------+-------+-------
 public | __diesel_schema_migrations | table | htyws
 public | rewards                    | table | htyws
 public | users                      | table | htyws
(3 rows)

htyws=# 
```

## 安装diesel_cli

```bash
$ cargo install diesel_cli --no-default-features --features postgres
```

## 初始化项目过程（已完成）

创建`.env`文件：

```bash
$ echo "DATABASE_URL=postgres://weli@localhost/htyws" > .env
```

里面是diesel要使用的数据库相关信息，上面就放数据库连接地址。

```bash
$ diesel setup
Creating migrations directory at: /Users/weli/works/htyws/migrations
```

## 创建用户表（初步工作完成）

创建第一个migration，创建一张`users`表：

```bash
$ diesel migration generate create_users
Creating migrations/2020-09-27-112838_create_users/up.sql
Creating migrations/2020-09-27-112838_create_users/down.sql
```

在`up.sql`里面添加内容：

```sql
CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  nickname VARCHAR UNIQUE NOT NULL
)
```

执行migration：

```bash
$ diesel migration run                                                                                                                                                                                                          19:20:27
Running migration 2020-09-27-112838_create_users
```

数据库表可以看到已经创建：

```bash
postgres=# \c htyws 
You are now connected to database "htyws" as user "weli".
htyws=# \dt
                  List of relations
 Schema |            Name            | Type  | Owner 
--------+----------------------------+-------+-------
 public | __diesel_schema_migrations | table | weli
 public | users                      | table | weli
(2 rows)

htyws=# select * from users;
 id | nickname 
----+----------
(0 rows)

htyws=# 
```

## 生成/更新schema文件（每次重构要做）

使用`diesel`的命令更新`schema.rs`（在项目根目录执行）：

```bash
$ diesel print-schema > src/schema.rs
```