db.dropDatabase(); 例:删除 bool 库 删除时,也是得先进入当前库下。 八:基本操作 插入 MongoDB存储的是文档,文档是json格式的象。 db.collectionName.insert(document); a):增加单篇文档,一条记录 例:db.stu.insert({"name":"lisi","age":24}); 注意:如果用户插入的
在SELECT语句中我们通常需要关注FROM、WHERE、ORDER BY等关键字。而在SHOW语句中,则要关注具体的对象类型,如SHOW DATABASES、SHOW TABLES等。 SELECT*FROMusersWHEREage>18ORDERBYname; 1. SHOWDATABASES; 1. 实战应用 在实际应用中,有可能会遇到异常情况,这时的处理方式尤为重要。 业务价值说明 使用SELECT查询可以大...
AI代码解释 <mysql:8.0.31:information_schema>selectname,concat(truncate(max_count/1024/1024,2),' MB')'databases_pages_size'frominnodb_metricswherename='buffer_pool_bytes_data';+---+---+|name|databases_pages_size|+---+---+|buffer_pool_bytes_data|16.28MB|+---+---+1rowinset(0.00sec)...
SHOW{BINARY|MASTER}SHOWBINLOG['log_name'][FROMpos][LIMIT[offset,]row_count]SHOWCHARACTERSET[like_or_where]SHOWCOLLATION[like_or_where]SHOW[FULL]COLUMNSFROMtbl_name[FROMdb_name]like_or_whereSHOWCREATEDATABASEdb_nameSHOWCREATEEVENTevent_nameSHOWCREATEFUNCTIONfunc_nameSHOWCREATEPROCEDUREproc_nameSHOWCREA...
<mysql:8.0.31:information_schema>select name,concat(truncate(max_count/1024/1024,2),' MB')'databases_pages_size'from innodb_metrics where name ='buffer_pool_bytes_data'; +---+---+ | name | databases_pages_size | +---+---+ | buffer_pool...
1 row in set (0.00 sec) Database pages :同样经过换算结果为 1042*16/1024=16.28MB,同样的方法,写条SQL,得出结果。 <mysql:8.0.31:information_schema>select name,concat(truncate(max_count/1024/1024,2),' MB') 'databases_pages_size' from innodb_metrics where name = 'buffer_pool_bytes_data';...
1 row in set (0.00 sec) Database pages :同样经过换算结果为 1042*16/1024=16.28MB,同样的方法,写条SQL,得出结果。 <mysql:8.0.31:information_schema>select name,concat(truncate(max_count/1024/1024,2),' MB') 'databases_pages_size' from innodb_metrics where name = 'buffer_pool_bytes_data';...
Semantic Kernel is an SDK for C#, Python, and Javaused to develop solutions with AI. SK includes libraries that wrap direct calls to databases, supporting vector search. Semantic Kernel is maintained in three languages, while the list of supported storage engines (known as "connectors") varies...
课程内容覆盖SQL、数据库、索引构建与优化、内存管理、并发控制、排序、分组聚合、查询规划、冲突与锁定、分布式数据库、内存数据库、Facebook Scuba、MongoDB、CockroachDB等内容,可以帮助构建系统的数据库原理与应用知识。 课程讲师Andy Pavlo,卡内基·梅隆大学计算机科学系副教授,研究兴趣是数据库管理系统中,特别是主内存...
Log in as the admin: mongo -u admin Check available databases: show dbs If yourschemaname is missing, create it using use yourschemaname Use the below command to create a new user:db.createUser( { user: "user", pwd: "abc123", roles: [ { role: "readWrite", db: "yourdata...