aws(学习笔记第十四课)
- 面向
NoSQL DB
的DynamoDB
学习内容:
- 开发一个任务
TODO
管理器
1. 主键,分区键和排序键
DynamoDB
的表定义和属性定义- 表定义(简单主键)
-
表定义的命名需要
系统名
+_
+表名
的形式,提前规划好前缀。因为DynamoDB
直接建立表,没有建立数据库,之后在个别的数据库里面建立表的过程,所以注意提前规划。 -
分区键 -简单的主键,由一个称为分区键 的属性组成。DynamoDB 使用分区键的值作为内部散列函数的输入。来自散列函数的输出决定了项目将存储到的分区 (DynamoDB 内部的物理存储)。在只有分区键的表中,任何两个项目都不能有相同的分区键值
-
表定义代码
注意,建表语句区分大小写
注意,这里建表的时候,建表的时候id
作为主键,不参与主键的name
和gender
不能定义shellaws dynamodb create-table --table-name stu_system_student \ --attribute-definitions AttributeName=id,AttributeType=S \ --key-schema AttributeName=id,KeyType=HASH \ --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5
定义之后如下所示:
shell$ aws dynamodb create-table --table-name stu_system_student \ --attribute-definitions AttributeName=id,AttributeType=S \ --key-schema AttributeName=id,KeyType=HASH \ --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5 { "TableDescription": { "AttributeDefinitions": [ { "AttributeName": "id", "AttributeType": "S" } ], "TableName": "stu_system_student", "KeySchema": [ { "AttributeName": "id", "KeyType": "HASH" } ], "TableStatus": "CREATING", "CreationDateTime": "2024-11-16T16:37:57.967000+08:00", "ProvisionedThroughput": { "NumberOfDecreasesToday": 0, "ReadCapacityUnits": 5, "WriteCapacityUnits": 5 }, "TableSizeBytes": 0, "ItemCount": 0, "TableArn": "arn:aws:dynamodb:ap-northeast-1:081353481087:table/stu_system_student", "TableId": "316d0a81-801b-451a-8fe1-57959f1906c6", "DeletionProtectionEnabled": false } }
执行
aws cli
查看表建立的状态shell$ aws dynamodb describe-table --table-name stu_system_student { "Table": { "AttributeDefinitions": [ { "AttributeName": "id", "AttributeType": "S" } ], "TableName": "stu_system_student", "KeySchema": [ { "AttributeName": "id", "KeyType": "HASH" } ], "TableStatus": "ACTIVE", "CreationDateTime": "2024-11-16T16:37:57.967000+08:00", "ProvisionedThroughput": { "NumberOfDecreasesToday": 0, "ReadCapacityUnits": 5, "WriteCapacityUnits": 5 }, "TableSizeBytes": 0, "ItemCount": 0, "TableArn": "arn:aws:dynamodb:ap-northeast-1:081353481087:table/stu_system_student", "TableId": "316d0a81-801b-451a-8fe1-57959f1906c6", "DeletionProtectionEnabled": false } }
-
- 表定义(复合主键)
-
分区键和排序键 - 称为复合主键,此类型的键由两个属性组成。第一个属性是分区键,第二个属性是排序键。
-
DynamoDB
使用分区键值作为对内部散列函数的输入。来自散列函数的输出决定了项目将存储到的分区 (DynamoDB
内部的物理存储)。具有相同分区键的所有项目按排序键值的排序顺序存储在一起。 -
在具有分区键和排序键的表中,两个项目可以具有相同的分区键值,但是,这两个项目必须具有不同的排序键值。
-
定义复合主键表
shellaws dynamodb create-table --table-name stu_system_score \ --attribute-definitions AttributeName=id,AttributeType=S \ AttributeName=lesson,AttributeType=S \ --key-schema AttributeName=id,KeyType=HASH \ AttributeName=lesson,KeyType=RANGE \ --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5
-
复合建表结果
shell$ aws dynamodb create-table --table-name stu_system_score \ --attribute-definitions AttributeName=id,AttributeType=S \ AttributeName=lesson,AttributeType=S \ --key-schema AttributeName=id,KeyType=HASH \ AttributeName=lesson,KeyType=RANGE \ --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5 { "TableDescription": { "AttributeDefinitions": [ { "AttributeName": "id", "AttributeType": "S" }, { "AttributeName": "lesson", "AttributeType": "S" } ], "TableName": "stu_system_score", "KeySchema": [ { "AttributeName": "id", "KeyType": "HASH" }, { "AttributeName": "lesson", "KeyType": "RANGE" } ], "TableStatus": "CREATING", "CreationDateTime": "2024-11-16T16:55:16.830000+08:00", "ProvisionedThroughput": { "NumberOfDecreasesToday": 0, "ReadCapacityUnits": 5, "WriteCapacityUnits": 5 }, "TableSizeBytes": 0, "ItemCount": 0, "TableArn": "arn:aws:dynamodb:ap-northeast-1:081353481087:table/stu_system_score", "TableId": "795a7ce6-8ecf-46c8-90f7-5c31e615886f", "DeletionProtectionEnabled": false } }
这里,
AttributeName=id
这个属性是分区键,不是主键。AttributeName=lesson
这个属性是排序键,他们两个属性组成联合主键。
-
- 表定义(简单主键)
2. 利用DynamoDB
编写一个任务管理器的例子
3. 创建表
- 创建两个表
todo-user
和todo-task
-
todo-user
shellaws dynamodb create-table --table-name todo-user \ --attribute-definitions AttributeName=uid,AttributeType=S \ --key-schema AttributeName=uid,KeyType=HASH \ --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5
-
todo-task
shellaws dynamodb create-table --table-name todo-task \ --attribute-definitions AttributeName=uid,AttributeType=S \ AttributeName=tid,AttributeType=N \ --key-schema AttributeName=uid,KeyType=HASH \ AttributeName=tid,KeyType=RANGE \ --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5
-
4. docopt
命令行代码框架以及node
整体程序
-
docopt
的cli
模板文件shellnodetodo Usage: nodetodo user-add <uid> <email> <phone> nodetodo user-rm <uid> nodetodo user-ls [--limit=<limit>] [--next=<id>] nodetodo user <uid> nodetodo task-add <uid> <description> [<category>] [--dueat=<yyyymmdd>] nodetodo task-rm <uid> <tid> nodetodo task-ls <uid> [<category>] [--overdue|--due|--withoutdue|--futuredue|--dueafter=<yyyymmdd>|--duebefore=<yyyymmdd>] [--limit=<limit>] [--next=<id>] nodetodo task-la <category> [--overdue|--due|--withoutdue|--futuredue|--dueafter=<yyyymmdd>|--duebefore=<yyyymmdd>] [--limit=<limit>] [--next=<id>] nodetodo task-done <uid> <tid> nodetodo -h | --help nodetodo --version Options: -h --help Show this screen. --version Show version. --limit=<limit> Maximum number of results [default: 10].
-
node
程序todo-task
的整体结构-
整体代码
nodevar fs = require('fs'); var docopt = require('docopt'); var moment = require("moment"); var AWS = require('aws-sdk'); var db = new AWS.DynamoDB({ "region": "ap-northeast-1" }); var cli = fs.readFileSync('./cli.txt', {"encoding": "utf8"}); var input = docopt.docopt(cli, {"version": "1.0", "argv": process.argv.splice(2)}); function getValue(attribute, type) { if (attribute === undefined) { return null; } return attribute[type]; } function mapTaskItem(item) { return { "tid": item.tid.N, "description": item.description.S, "created": item.created.N, "due": getValue(item.due, 'N'), "category": getValue(item.category, 'S'), "completed": getValue(item.completed, 'N') }; } function mapUserItem(item) { return { "uid": item.uid.S, "email": item.email.S, "phone": item.phone.S }; } if (input['user-add'] === true) { var params = { "Item": { "uid": { "S": input['<uid>'] }, "email": { "S": input['<email>'] }, "phone": { "S": input['<phone>'] } }, "TableName": "todo-user", "ConditionExpression": "attribute_not_exists(uid)" }; db.putItem(params, function(err) { if (err) { console.error('error', err); } else { console.log('user added with uid ' + input['<uid>']); } }); } else if (input['user-rm'] === true) { var params = { "Key": { "uid": { "S": input['<uid>'] } }, "TableName": "todo-user" }; db.deleteItem(params, function(err) { if (err) { console.error('error', err); } else { console.log('user removed with uid ' + input['<uid>']); } }); } else if (input['user-ls'] === true) { var params = { "TableName": "todo-user", "Limit": input['--limit'] }; if (input['--next'] !== null) { params.ExclusiveStartKey = { "uid": { "S": input['--next'] } }; } db.scan(params, function(err, data) { if (err) { console.error('error', err); } else { console.log('users', data.Items.map(mapUserItem)); if (data.LastEvaluatedKey !== undefined) { console.log('more users available with --next=' + data.LastEvaluatedKey.uid.S); } } }); } else if (input['user'] === true) { var params = { "Key": { "uid": { "S": input['<uid>'] } }, "TableName": "todo-user" }; db.getItem(params, function(err, data) { if (err) { console.error('error', err); } else { if (data.Item) { console.log('user with uid ' + input['<uid>'], mapUserItem(data.Item)); } else { console.error('user with uid ' + input['<uid>'] + ' not found'); } } }); } else if (input['task-add'] === true) { var tid = Date.now(); var params = { "Item": { "uid": { "S": input['<uid>'] }, "tid": { "N": tid.toString() }, "description": { "S": input['<description>'] }, "created": { "N": moment().format("YYYYMMDD") } }, "TableName": "todo-task", "ConditionExpression": "attribute_not_exists(uid) and attribute_not_exists(tid)" }; if (input['--dueat'] !== null) { params.Item.due = { "N": input['--dueat'] }; } if (input['<category>'] !== null) { params.Item.category = { "S": input['<category>'] }; } db.putItem(params, function(err) { if (err) { console.error('error', err); } else { console.log('task added with tid ' + tid); } }); } else if (input['task-rm'] === true) { var params = { "Key": { "uid": { "S": input['<uid>'] }, "tid": { "N": input['<tid>'] } }, "TableName": "todo-task" }; db.deleteItem(params, function(err) { if (err) { console.error('error', err); } else { console.log('task removed with tid ' + input['<tid>']); } }); } else if (input['task-ls'] === true) { var params = { "KeyConditionExpression": "uid = :uid", "ExpressionAttributeValues": { ":uid": { "S": input['<uid>'] } }, "TableName": "todo-task", "Limit": input['--limit'] }; if (input['--next'] !== null) { params.KeyConditionExpression += ' AND tid > :next'; params.ExpressionAttributeValues[':next'] = { "N": input['--next'] }; } if (input['--overdue'] === true) { params.FilterExpression = "due < :yyyymmdd"; params.ExpressionAttributeValues[':yyyymmdd'] = {"N": moment().format("YYYYMMDD")}; } else if (input['--due'] === true) { params.FilterExpression = "due = :yyyymmdd"; params.ExpressionAttributeValues[':yyyymmdd'] = {"N": moment().format("YYYYMMDD")}; } else if (input['--withoutdue'] === true) { params.FilterExpression = "attribute_not_exists(due)"; } else if (input['--futuredue'] === true) { params.FilterExpression = "due > :yyyymmdd"; params.ExpressionAttributeValues[':yyyymmdd'] = {"N": moment().format("YYYYMMDD")}; } else if (input['--dueafter'] !== null) { params.FilterExpression = "due > :yyyymmdd"; params.ExpressionAttributeValues[':yyyymmdd'] = {"N": input['--dueafter']}; } else if (input['--duebefore'] !== null) { params.FilterExpression = "due < :yyyymmdd"; params.ExpressionAttributeValues[':yyyymmdd'] = {"N": input['--duebefore']}; } if (input['<category>'] !== null) { if (params.FilterExpression === undefined) { params.FilterExpression = ''; } else { params.FilterExpression += ' AND '; } params.FilterExpression += 'category = :category'; params.ExpressionAttributeValues[':category'] = { "S": input['<category>'] }; } db.query(params, function(err, data) { if (err) { console.error('error', err); } else { console.log('tasks', data.Items.map(mapTaskItem)); if (data.LastEvaluatedKey !== undefined) { console.log('more tasks available with --next=' + data.LastEvaluatedKey.tid.N); } } }); } else if (input['task-la'] === true) { var params = { "KeyConditionExpression": "category = :category", "ExpressionAttributeValues": { ":category": { "S": input['<category>'] } }, "TableName": "todo-task", "IndexName": "category-index", "Limit": input['--limit'] }; if (input['--next'] !== null) { params.KeyConditionExpression += ' AND tid > :next'; params.ExpressionAttributeValues[':next'] = { "N": input['--next'] }; } if (input['--overdue'] === true) { params.FilterExpression = "due < :yyyymmdd"; params.ExpressionAttributeValues[':yyyymmdd'] = {"N": moment().format("YYYYMMDD")}; } else if (input['--due'] === true) { params.FilterExpression = "due = :yyyymmdd"; params.ExpressionAttributeValues[':yyyymmdd'] = {"N": moment().format("YYYYMMDD")}; } else if (input['--withoutdue'] === true) { params.FilterExpression = "attribute_not_exists(due)"; } else if (input['--futuredue'] === true) { params.FilterExpression = "due > :yyyymmdd"; params.ExpressionAttributeValues[':yyyymmdd'] = {"N": moment().format("YYYYMMDD")}; } else if (input['--dueafter'] !== null) { params.FilterExpression = "due > :yyyymmdd"; params.ExpressionAttributeValues[':yyyymmdd'] = {"N": input['--dueafter']}; } else if (input['--duebefore'] !== null) { params.FilterExpression = "due < :yyyymmdd"; params.ExpressionAttributeValues[':yyyymmdd'] = {"N": input['--duebefore']}; } db.query(params, function(err, data) { if (err) { console.error('error', err); } else { console.log('tasks', data.Items.map(mapTaskItem)); if (data.LastEvaluatedKey !== undefined) { console.log('more tasks available with --next=' + data.LastEvaluatedKey.tid.N); } } }); } else if (input['task-done'] === true) { var params = { "Key": { "uid": { "S": input['<uid>'] }, "tid": { "N": input['<tid>'] } }, "UpdateExpression": "SET completed = :yyyymmdd", "ExpressionAttributeValues": { ":yyyymmdd": { "N": moment().format("YYYYMMDD") } }, "TableName": "todo-task" }; db.updateItem(params, function(err) { if (err) { console.error('error', err); } else { console.log('task completed with tid ' + input['<tid>']); } }); }
-
5. 进行操作以及代码解析
-
增加用户
-
命令执行
shellnode index.js user-add '001' 'finlay@163.com' '1234567'
-
实现代码
javascriptvar params = { "Item": { "uid": { "S": input['<uid>'] }, "email": { "S": input['<email>'] }, "phone": { "S": input['<phone>'] } }, "TableName": "todo-user", "ConditionExpression": "attribute_not_exists(uid)" };
-
-
查询用户
-
执行命令
shellnode index.js user-ls
-
实现代码
javascript} else if (input['user-ls'] === true) { var params = { "TableName": "todo-user", "Limit": input['--limit'] }; if (input['--next'] !== null) { params.ExclusiveStartKey = { "uid": { "S": input['--next'] } }; } db.scan(params, function(err, data) { if (err) { console.error('error', err); } else { console.log('users', data.Items.map(mapUserItem)); if (data.LastEvaluatedKey !== undefined) { console.log('more users available with --next=' + data.LastEvaluatedKey.uid.S); } } });
-
6. 查询用户表数据
- 执行查询用户命令
-
查询用户
shell$ node index.js user-ls users [ { uid: '001', email: 'finlay@163.com', phone: '13512345678' } ]
-
实现代码
javascript} else if (input['user-ls'] === true) { var params = { "TableName": "todo-user", "Limit": input['--limit'] }; if (input['--next'] !== null) { params.ExclusiveStartKey = { "uid": { "S": input['--next'] } }; } db.scan(params, function(err, data) { if (err) { console.error('error', err); } else { console.log('users', data.Items.map(mapUserItem)); if (data.LastEvaluatedKey !== undefined) { console.log('more users available with --next=' + data.LastEvaluatedKey.uid.S); } } });
-
7. 追加task
表数据
- 执行追加命令
-
执行追加
task
命令shellnode index.js task-add 001 "this is a emergency job" --dueat=20241201
-
实现代码
javascript} else if (input['task-add'] === true) { var tid = Date.now(); var params = { "Item": { "uid": { "S": input['<uid>'] }, "tid": { "N": tid.toString() }, "description": { "S": input['<description>'] }, "created": { "N": moment().format("YYYYMMDD") } }, "TableName": "todo-task", "ConditionExpression": "attribute_not_exists(uid) and attribute_not_exists(tid)" }; if (input['--dueat'] !== null) { params.Item.due = { "N": input['--dueat'] }; } if (input['<category>'] !== null) { params.Item.category = { "S": input['<category>'] }; } db.putItem(params, function(err) { if (err) { console.error('error', err); } else { console.log('task added with tid ' + tid); } });
-
8. 查询task
表数据
- 执行
task
查询命令-
执行查询
task
命令shellnode index.js task-ls 001
-
代码实现
javascript} else if (input['task-ls'] === true) { var params = { "KeyConditionExpression": "uid = :uid", "ExpressionAttributeValues": { ":uid": { "S": input['<uid>'] } }, "TableName": "todo-task", "Limit": input['--limit'] }; if (input['--next'] !== null) { params.KeyConditionExpression += ' AND tid > :next'; params.ExpressionAttributeValues[':next'] = { "N": input['--next'] }; } if (input['--overdue'] === true) { params.FilterExpression = "due < :yyyymmdd"; params.ExpressionAttributeValues[':yyyymmdd'] = {"N": moment().format("YYYYMMDD")}; } else if (input['--due'] === true) { params.FilterExpression = "due = :yyyymmdd"; params.ExpressionAttributeValues[':yyyymmdd'] = {"N": moment().format("YYYYMMDD")}; } else if (input['--withoutdue'] === true) { params.FilterExpression = "attribute_not_exists(due)"; } else if (input['--futuredue'] === true) { params.FilterExpression = "due > :yyyymmdd"; params.ExpressionAttributeValues[':yyyymmdd'] = {"N": moment().format("YYYYMMDD")}; } else if (input['--dueafter'] !== null) { params.FilterExpression = "due > :yyyymmdd"; params.ExpressionAttributeValues[':yyyymmdd'] = {"N": input['--dueafter']}; } else if (input['--duebefore'] !== null) { params.FilterExpression = "due < :yyyymmdd"; params.ExpressionAttributeValues[':yyyymmdd'] = {"N": input['--duebefore']}; } if (input['<category>'] !== null) { if (params.FilterExpression === undefined) { params.FilterExpression = ''; } else { params.FilterExpression += ' AND '; } params.FilterExpression += 'category = :category'; params.ExpressionAttributeValues[':category'] = { "S": input['<category>'] }; } db.query(params, function(err, data) { if (err) { console.error('error', err); } else { console.log('tasks', data.Items.map(mapTaskItem)); if (data.LastEvaluatedKey !== undefined) { console.log('more tasks available with --next=' + data.LastEvaluatedKey.tid.N); } } });
-
9. 查询表数据的三种方式
-
提供键来获取数据
-
指定主键的属性
-
使用分区键加上过滤条件查询
-
-
二级索引查询
-
二级索引的原理
下面的例子category
作为索引的例子,通过再做出一个索引表,DynamoDB
增加一个原表的另一个只读索引表。
-
作成二级索引
注意,json
如果在命令行里面,命令行对于json
这里就不能使用\换行符!shellaws dynamodb update-table --table-name todo-task \ --attribute-definitions AttributeName=uid,AttributeType=S \ AttributeName=tid,AttributeType=N \ AttributeName=category,AttributeType=S \ --global-secondary-index-updates '[{"Create": {"IndexName": "category-index","KeySchema":[{"AttributeName":"category","KeyType":"HASH"},{"AttributeName": "tid", "KeyType": "RANGE"}],"Projection": {"ProjectionType": "ALL"},"ProvisionedThroughput":{"ReadCapacityUnits":5,"WriteCapacityUnits":5}}}]'
-
- 扫描查询
如果实在没有主键,分区键,排序键进行查找,那么选择full table scan
也是没有办法的事情。