--以dba身份登录 C:\Users\Administratorgt;sqlplus / as sysdba --创建用户 SQLgt; create user bfzg0828 identified by bfzg
--以dba身份登录
C:\Users\Administrator>sqlplus / as sysdba
--创建用户
SQL> create user bfzg0828 identified by bfzg0828 default tablespace users quota
unlimited on users;
--授予连接角色,资源角色给用户
SQL> grant connect,resource to bfzg0828;
授权成功。
--授权创建数据链接
SQL> grant create table,create database link to bfzg0828;
授权成功。
--创建目录
SQL> create or replace directory Oracle_exp as 'D:\oracle';
目录已创建。
--在物理机上d盘创建文件oracle
......
--给用户授予目录读写权限
SQL> grant read,write on directory oracle_exp to bfzg0828;
grant read,write on directory oracle_exp to bfzg;
授权成功。
--以bfzg0828用户登陆
SQL> conn bfzg0828/bfzg0828
已连接。
--创建网络数据库链接
SQL> create database link test113 connect to btv10_bz identified by btv10_bz using '192.168.0.66:1521/bttest';
数据库链接已创建。
--查询创建的网络链接
SQL> select * from global_name@test113;
GLOBAL_NAME
-----------------------------------------------
BTTEST
SQL>
--使用expdp导出远程数据库到本地目录d:\oracle\bfzg0828.dmp
C:\Users\Administrator>expdp bfzg0828/bfzg0828@orcl11g directory=DIR_EXP dumpfile=bfzg0828.dmp logfile=bfzg0828.log network_link=test113
--导出成功后,,使用impdp导入到本地库
--这里是新建的用户bfzg用户,拥有connect,resouce角色权限,table_exists_action=replace表示,如果表存在则替换,imp没有功能
impdp bfzg/bfzg directory=oracle_exp dumpfile=BFZG0828.DMP remap_schema=btv10_bz:bfzg exclude=statistics table_exists_action=replace
注btv10_bz为导出用户,bfzg为本次导入用户
BFZG0828.DMP导出用户是btv10_bz(btv10_bz/btv10_bz@192.168.0.66:1521/bttest)
--导入单个表
impdp bfzg/bfzg directory=oracle_exp dumpfile=BFZG0828.DMP tables=btv10_bz.bt_corp remap_schema=btv10_bz:bfzg exclude=statistics table_exists_action=replace
--------------------------------------分割线 --------------------------------------
Ubuntu 14.04下安装MySQL
《MySQL权威指南(原书第2版)》清晰中文扫描版 PDF
Ubuntu 14.04 LTS 安装 LNMP Nginx\PHP5 (PHP-FPM)\MySQL
Ubuntu 14.04下搭建MySQL主从服务器
Ubuntu 12.04 LTS 构建高可用分布式 MySQL 集群
Ubuntu 12.04下源代码安装MySQL5.6以及Python-MySQLdb
MySQL-5.5.38通用二进制安装
--------------------------------------分割线 --------------------------------------
本文永久更新链接地址:

ACID attributes include atomicity, consistency, isolation and durability, and are the cornerstone of database design. 1. Atomicity ensures that the transaction is either completely successful or completely failed. 2. Consistency ensures that the database remains consistent before and after a transaction. 3. Isolation ensures that transactions do not interfere with each other. 4. Persistence ensures that data is permanently saved after transaction submission.

MySQL is not only a database management system (DBMS) but also closely related to programming languages. 1) As a DBMS, MySQL is used to store, organize and retrieve data, and optimizing indexes can improve query performance. 2) Combining SQL with programming languages, embedded in Python, using ORM tools such as SQLAlchemy can simplify operations. 3) Performance optimization includes indexing, querying, caching, library and table division and transaction management.

MySQL uses SQL commands to manage data. 1. Basic commands include SELECT, INSERT, UPDATE and DELETE. 2. Advanced usage involves JOIN, subquery and aggregate functions. 3. Common errors include syntax, logic and performance issues. 4. Optimization tips include using indexes, avoiding SELECT* and using LIMIT.

MySQL is an efficient relational database management system suitable for storing and managing data. Its advantages include high-performance queries, flexible transaction processing and rich data types. In practical applications, MySQL is often used in e-commerce platforms, social networks and content management systems, but attention should be paid to performance optimization, data security and scalability.

The relationship between SQL and MySQL is the relationship between standard languages and specific implementations. 1.SQL is a standard language used to manage and operate relational databases, allowing data addition, deletion, modification and query. 2.MySQL is a specific database management system that uses SQL as its operating language and provides efficient data storage and management.

InnoDB uses redologs and undologs to ensure data consistency and reliability. 1.redologs record data page modification to ensure crash recovery and transaction persistence. 2.undologs records the original data value and supports transaction rollback and MVCC.

Key metrics for EXPLAIN commands include type, key, rows, and Extra. 1) The type reflects the access type of the query. The higher the value, the higher the efficiency, such as const is better than ALL. 2) The key displays the index used, and NULL indicates no index. 3) rows estimates the number of scanned rows, affecting query performance. 4) Extra provides additional information, such as Usingfilesort prompts that it needs to be optimized.

Usingtemporary indicates that the need to create temporary tables in MySQL queries, which are commonly found in ORDERBY using DISTINCT, GROUPBY, or non-indexed columns. You can avoid the occurrence of indexes and rewrite queries and improve query performance. Specifically, when Usingtemporary appears in EXPLAIN output, it means that MySQL needs to create temporary tables to handle queries. This usually occurs when: 1) deduplication or grouping when using DISTINCT or GROUPBY; 2) sort when ORDERBY contains non-index columns; 3) use complex subquery or join operations. Optimization methods include: 1) ORDERBY and GROUPB


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