新手使用mongodb
# mongo
mongo适用于大数据量，高并发，轻量事物型系统
## devops
### 创建管理员账户
1. 以非授权模式启动mongod
```sh
mongod --dbpath /usr/local/var/mongodb --logpath /usr/local/var/log/mongodb/mongo.log --fork
```
2. 创建管理用户admin
`使用mongosh连接进去`
```bash
test> use admin
switched to db admin
admin> db.createUser({
... user:"admin",
... pwd:"admin123456",
... roles:[{role:"userAdminAnyDatabase",db:"admin"}]
... });
{ ok: 1 }
#查看用户,另外还可以使用db.system.users.find()
admin> show users
[
{
_id: 'admin.admin',
userId: UUID("554560b1-e47b-44d9-8d3a-5f7ae5c933eb"),
user: 'admin',
db: 'admin',
roles: [ { role: 'userAdminAnyDatabase', db: 'admin' } ],
mechanisms: [ 'SCRAM-SHA-1', 'SCRAM-SHA-256' ]
}
]
#退出来
admin> quit
```
3. 停止数据库
```sh
killall `pidof mongod`
```
### 创建业务账户
1. 以授权模式启动
```bash
```sh
mongod --auth --dbpath /usr/local/var/mongodb --logpath /usr/local/var/log/mongodb/mongo.log --fork
```
```
2. 使用admin登录
```sh
# 可直接使用mongosh进去后使用db.auth('admin','admin123456')再认证
mongosh -u admin -p
```
3. 创建业务用户
```sh
test> use biz
biz> db.createUser({user:"webopr",pwd:"123456",roles:[{role:"readWrite",db:"biz"}]})
{ ok: 1 }
```
4. 使用webopr登录
```sh
test> use biz
switched to db biz
biz> db.auth('webopr','123456')
{ ok: 1 }
biz>
biz> show tables;
# 插入数据
biz> db.users.insertOne({uid:0,age:19,name:"EdgeCross",uin:"skyhawk"})
{
acknowledged: true,
insertedId: ObjectId("6438fa7dda4faacf8d683e85")
}
# 查询刚插入的数据
biz> db.users.find();
[
{
_id: ObjectId("6438fa7dda4faacf8d683e85"),
uid: 0,
age: 19,
name: 'EdgeCross',
uin: 'skyhawk'
}
]
```
## 客户端编码
### options包
在options包, 可用来设置客户端选项(ClientOptions)。
```go
// 新建客户端选项
func Client()*ClientOptions
// 连接字符串，DSN
func (c *ClientOptions) GetURI() string
func (c *ClientOptions) ApplyURI(uri string) *ClientOptions
// 参数设置... 一些参数可通过uri参数设置
```
#### 连接字符串
```go
"mongodb://user:password@host:port/db?param1=value1¶m2=value2"
```
### mongo包
#### Client
一个Client对象是一个连接池，它是并发安全的。它可以自动地打开和关闭连接，并维护一个空闲的连接池。
连接池的配置选项可通过options.ClientOptions配置。
```go
// 调用NewClient创建Client对象，并调用Connect方法初始化它。
func Connect(ctx context.Context, opts ...*options.ClientOptions) (*Client, error)
// 创建client对象
func NewClient(opts ...*options.ClientOptions) (*Client, error)
// 通过启动后台监听协程来初始化Client，如果c通过NewClient函数创建，该方法必须在client使用之前被调用。
func (c *Client) Connect(ctx context.Context) error
// 关闭网络连接
func (c *Client) Disconnect(ctx context.Context) error
// Ping 用于验证连接是否建立起来了（与数据库的网络连接）
func (c *Client) Ping(ctx context.Context, rp *readpref.ReadPref) error
// 根据给定的选项创建一个新的会话，调用StartSession是线程安全的，但是返回的session不是线程安全的。
func (c *Client) StartSession(opts ...*options.SessionOptions) (Session, error)
// 获取数据库句柄
func (c *Client) Database(name string, opts ...*options.DatabaseOptions) *Database
func (c *Client) ListDatabases(ctx context.Context, filter interface{}, opts ...*options.ListDatabasesOptions)
func (c *Client) ListDatabaseNames(ctx context.Context, filter interface{}, opts ...*options.ListDatabasesOptions) ([]string, error)
// session
func WithSession(ctx context.Context, sess Session, fn func(SessionContext) error) error
func (c *Client) UseSession(ctx context.Context, fn func(SessionContext) error) error
func (c *Client) UseSessionWithOptions(ctx context.Context, opts *options.SessionOptions, fn func(SessionContext) error) error
func (c *Client) NumberSessionsInProgress() int
// changestream
func (c *Client) Watch(ctx context.Context, pipeline interface{},
opts ...*options.ChangeStreamOptions) (*ChangeStream, error)
```
#### Database
描述一个mongoDB数据库，是线程安全的。
```go
// 获得一个集合句柄
func (db *Database) Collection(name string, opts ...*options.CollectionOptions) *Collection
// 在数据库上执行一个聚合命令
func (db *Database) Aggregate(ctx context.Context, pipeline interface{},
opts ...*options.AggregateOptions) (*Cursor, error)
// 执行命令
func (db *Database) RunCommand(ctx context.Context, runCommand interface{}, opts ...*options.RunCmdOptions) *SingleResult
func (db *Database) RunCommandCursor(ctx context.Context, runCommand interface{}, opts ...*options.RunCmdOptions) (*Cursor, error)
// 在数据库上删除
func (db *Database) Drop(ctx context.Context) error
// 列出集合
func (db *Database) ListCollectionSpecifications(ctx context.Context, filter interface{},
opts ...*options.ListCollectionsOptions) ([]*CollectionSpecification, error)
func (db *Database) ListCollections(ctx context.Context, filter interface{}, opts ...*options.ListCollectionsOptions) (*Cursor, error)
// 数据库ChangeStream
func (db *Database) Watch(ctx context.Context, pipeline interface{},
opts ...*options.ChangeStreamOptions) (*ChangeStream, error)
// 显示的创建集合，如果集合存在，返回错误
func (db *Database) CreateCollection(ctx context.Context, name string, opts ...*options.CreateCollectionOptions) error
// 创建视图，视图是干什么的?
func (db *Database) CreateView(ctx context.Context, viewName, viewOn string, pipeline interface{},
opts ...*options.CreateViewOptions) error
```
#### Collection
描述一个mongoDB集合，是线程安全的。
```go
// 执行一个批量写操作
func (coll *Collection) BulkWrite(ctx context.Context, models []WriteModel,
opts ...*options.BulkWriteOptions) (*BulkWriteResult, error)
// 插入
func (coll *Collection) InsertOne(ctx context.Context, document interface{},
opts ...*options.InsertOneOptions) (*InsertOneResult, error)
func (coll *Collection) InsertMany(ctx context.Context, documents []interface{},
opts ...*options.InsertManyOptions) (*InsertManyResult, error)
// 删除
func (coll *Collection) DeleteOne(ctx context.Context, filter interface{},
opts ...*options.DeleteOptions) (*DeleteResult, error)
func (coll *Collection) DeleteMany(ctx context.Context, filter interface{},
opts ...*options.DeleteOptions) (*DeleteResult, error)
// 更新
func (coll *Collection) UpdateByID(ctx context.Context, id interface{}, update interface{},
opts ...*options.UpdateOptions) (*UpdateResult, error)
func (coll *Collection) UpdateOne(ctx context.Context, filter interface{}, update interface{},
opts ...*options.UpdateOptions) (*UpdateResult, error)
func (coll *Collection) UpdateMany(ctx context.Context, filter interface{}, update interface{},
opts ...*options.UpdateOptions) (*UpdateResult, error)
func (coll *Collection) ReplaceOne(ctx context.Context, filter interface{},
replacement interface{}, opts ...*options.ReplaceOptions) (*UpdateResult, error)
// 执行聚合命令
func (coll *Collection) Aggregate(ctx context.Context, pipeline interface{},
opts ...*options.AggregateOptions) (*Cursor, error)
// 统计文档数量
func (coll *Collection) CountDocuments(ctx context.Context, filter interface{},
opts ...*options.CountOptions) (int64, error)
func (coll *Collection) EstimatedDocumentCount(ctx context.Context,
opts ...*options.EstimatedDocumentCountOptions) (int64, error)
func (coll *Collection) Distinct(ctx context.Context, fieldName string, filter interface{},
opts ...*options.DistinctOptions) ([]interface{}, error)
// 查询
func (coll *Collection) Find(ctx context.Context, filter interface{},
opts ...*options.FindOptions) (cur *Cursor, err error)
func (coll *Collection) FindOne(ctx context.Context, filter interface{},
opts ...*options.FindOneOptions) *SingleResult
func (coll *Collection) FindOneAndDelete(ctx context.Context, filter interface{},
opts ...*options.FindOneAndDeleteOptions) *SingleResult
func (coll *Collection) FindOneAndReplace(ctx context.Context, filter interface{},
replacement interface{}, opts ...*options.FindOneAndReplaceOptions) *SingleResult
func (coll *Collection) FindOneAndUpdate(ctx context.Context, filter interface{},
update interface{}, opts ...*options.FindOneAndUpdateOptions) *SingleResult
// 监听
func (coll *Collection) Watch(ctx context.Context, pipeline interface{},
opts ...*options.ChangeStreamOptions) (*ChangeStream, error)
// 索引视图
func (coll *Collection) Indexes() IndexView
// 销毁
func (coll *Collection) Drop(ctx context.Context) error
```
#### ___Cursor___
用于迭代文档流。通过Decode或者通过Current字典访问原始的BSON都可以将一个数据库文档解码为一个Go类型。不是线程安全的哦
```go
func (c *Cursor) Next(ctx context.Context) bool
func (c *Cursor) TryNext(ctx context.Context) bool
// 将bson反序列化到val中
func (c *Cursor) Decode(val interface{})
func (c *Cursor) Err() error
func (c *Cursor) Close(ctx context.Context) error
func (c *Cursor) All(ctx context.Context, results interface{}) error
```
