MySQL和Oracle对比学习之数据字典元数据(r4笔记第33天)

MySQL和Oracle虽然在架构上有很大的不同，但是如果从某些方面比较起来，它们有些方面也是相通的。 毕竟学习的主线是MySQL，所以会从MySQL的角度来对比Oracle的一些功能。大体总结了以下的内容，欢迎大家拍砖， 查看当前的数据库名 mysql> SELECT DATABASE(); +------------+ | DATABASE() | +------------+ | test | +------------+ 1 row in set (0.00 sec) +++ Oracle的实现方法 ++++ 因为架构的不同，所以列举了数据库，实例级的查询方法。 方法一，通过数据库参数来查看 SQL> show parameter instance_name NAME TYPE VALUE ------------------------------------ --------------------------------- ------------------------------ instance_name string TRUABP4 方法二：通过数据字典来查看 数据库级 SQL> select name from v$database; NAME --------------------------- TRUABP4 实例级 SQL> select instance_name from v$instance; INSTANCE_NAME ------------------------------------------------ TRUABP4 方法三：通过内置函数来实现，这种方法相比前两种更为通用。 SQL> select sys_context('USERENV','instance_name') from dual; SYS_CONTEXT('USERENV','INSTANCE_NAME') ---------------------------------------------------- TRUABP4 得到数据库创建的脚本 得到数据库名为mysql的创建脚本，毕竟在架构实现上不同，有点类似oracle中的用户级别。 mysql> show create database mysql; +----------+------------------------------------------------------------------+ | Database | Create Database | +----------+------------------------------------------------------------------+ | mysql | CREATE DATABASE `mysql` /*!40100 DEFAULT CHARACTER SET latin1 */ | +----------+------------------------------------------------------------------+ 1 row in set (0.00 sec) +++ Oracle的实现方法 ++++ Oracle中的实现方式相比要复杂很多。叫法一样，但是实现还是有很大的差别。 CREATE DATABASE mynewdb USER SYS IDENTIFIED BY pz6r58 USER SYSTEM IDENTIFIED BY y1tz5p LOGFILE GROUP 1 ('/u01/oracle/oradata/mynewdb/redo01.log') SIZE 100M, GROUP 2 ('/u01/oracle/oradata/mynewdb/redo02.log') SIZE 100M, GROUP 3 ('/u01/oracle/oradata/mynewdb/redo03.log') SIZE 100M MAXLOGFILES 5 MAXLOGMEMBERS 5 MAXLOGHISTORY 1 MAXDATAFILES 100 MAXINSTANCES 1 CHARACTER SET US7ASCII NATIONAL CHARACTER SET AL16UTF16 DATAFILE '/u01/oracle/oradata/mynewdb/system01.dbf' SIZE 325M REUSE EXTENT MANAGEMENT LOCAL SYSAUX DATAFILE '/u01/oracle/oradata/mynewdb/sysaux01.dbf' SIZE 325M REUSE DEFAULT TEMPORARY TABLESPACE tempts1 TEMPFILE '/u01/oracle/oradata/mynewdb/temp01.dbf' SIZE 20M REUSE UNDO TABLESPACE undotbs DATAFILE '/u01/oracle/oradata/mynewdb/undotbs01.dbf' SIZE 200M REUSE AUTOEXTEND ON MAXSIZE UNLIMITED; 查看当前的用户 mysql> SELECT USER(); +----------------+ | USER() | +----------------+ | root@localhost | +----------------+ 1 row in set (0.00 sec) +++ Oracle的实现方法 ++++ 方法一，通过sql*plus中的show user命令杰克得到 SQL> show user USER is "N1" 方法二：通过内置函数来实现，比较通用的方式。 SQL> select sys_context('USERENV','current_user') from dual; SYS_CONTEXT('USERENV','CURRENT_USER') -------------------------------------------------- N1 查看含有的表信息 mysql> show tables; +---------------------------+ | Tables_in_mysql | +---------------------------+ | columns_priv | | db | | event | | func | | general_log | | help_category | | time_zone_transition_type | | user | +---------------------------+ 28 rows in set (0.00 sec) +++ Oracle的实现方法 ++++ 方法一：通过cat同义词来实现 SQL> select *from cat where rownum<3; TABLE_NAME TABTYPE ------------------ --------------------- AAA TABLE AAAA TABLE 方法二：通过tab同义词来实现 SQL> select *from tab where rownum<3; TNAME TABTYPE CLUSTERID ------------------ --------------------- ---------- AAA TABLE AAAA TABLE 方法三：通过数据字典user_tables来实现 SQL> select table_name from user_tables where rownum<3; TABLE_NAME ------------------ AAA AAAA 查看指定数据库中的表信息 比如查询数据库名为mysql里面含有的表。 mysql> show tables from mysql; +---------------------------+ | Tables_in_mysql | +---------------------------+ | columns_priv | | db | | event | | func | | general_log | | help_category | | help_keyword | | help_relation | | time_zone_transition_type | | user | +---------------------------+ 28 rows in set (0.00 sec) +++ Oracle的实现方法 ++++ Oracle中的实现还是根据数据字典表*_tables SQL> select table_name from all_tables where owner='REFWORK'; TABLE_NAME ------------------------------ OFFER 查看test数据库中的表temp结构 >mysqlshow test temp Database: test Table: temp +---------+-------------+-----------------+------+-----+---------+-------------- | Field | Type | Collation | Null | Key | Default | Extra +---------+-------------+-----------------+------+-----+---------+-------------- | id | int(11) | | NO | PRI | | auto_incremen | char | char(50) | utf8_general_ci | NO | MUL | | | varchar | varchar(50) | utf8_general_ci | NO | MUL | | | text | text | utf8_general_ci | NO | MUL | | +---------+-------------+-----------------+------+-----+---------+-------------- +++ Oracle的实现方法 ++++ 可以通过all_tab_cols来实现 select table_name,column_name from all_tab_cols where owner='N1' and table_name='TEST'; 查看表的建表语句 mysql> show create table event\G *************************** 1. row *************************** Table: event Create Table: CREATE TABLE `event` ( `db` char(64) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '', `name` char(64) NOT NULL DEFAULT '', `body` longblob NOT NULL, `definer` char(77) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '', `execute_at` datetime DEFAULT NULL, `body_utf8` longblob, PRIMARY KEY (`db`,`name`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COMMENT='Events' 1 row in set (0.00 sec) +++ Oracle的实现方法 ++++ oracle中一直直观的方式是使用dbms_metadata.get_ddl来实现 SQL> select DBMS_METADATA.GET_DDL(object_type=>'TABLE',name=>'CSM_OFFER')from dual DBMS_METADATA.GET_DDL(OBJECT_TYPE=>'TABLE',NAME=>'CSM_OFFER') -------------------------------------------------------------------------------- CREATE TABLE "REFWORK"."OFFER" ( "OWNER" VARCHAR2(30) NOT NULL ENABLE, "OBJECT_NAME" VARCHAR2(30) NOT NULL ENABLE, "SUBOBJECT_NAME" VARCHAR2(30), "OBJECT_ID" NUMBER NOT NULL ENABLE, "DATA_OBJECT_ID" NUMBER, "OBJECT_TYPE" VARCHAR2(19), "CREATED" DATE NOT NULL ENABLE, "LAST_DDL_TIME" DATE NOT NULL ENABLE, "TIMESTAMP" VARCHAR2(19)... 得到表结构的信息 mysql> desc columns_priv -> ; +-------------+----------------------------------------------+------+-----+----- | Field | Type | Null | Key | Defa +-------------+----------------------------------------------+------+-----+----- | Host | char(60) | NO | PRI | | Db | char(64) | NO | PRI | | User | char(16) | NO | PRI | | Table_name | char(64) | NO | PRI | | Column_name | char(64) | NO | PRI | | Timestamp | timestamp | NO | | CURR | Column_priv | set('Select','Insert','Update','References') | NO | | +-------------+----------------------------------------------+------+-----+----- 7 rows in set (0.01 sec) +++ Oracle的实现方法 ++++ 这一点完全一样 SQL> desc offer Name Null? Type ----------------------------------------- -------- ---------------------------- OWNER NOT NULL VARCHAR2(30) OBJECT_NAME NOT NULL VARCHAR2(30) SUBOBJECT_NAME VARCHAR2(30) OBJECT_ID NOT NULL NUMBER DATA_OBJECT_ID NUMBER OBJECT_TYPE VARCHAR2(19) CREATED NOT NULL DATE LAST_DDL_TIME NOT NULL DATE TIMESTAMP VARCHAR2(19) STATUS VARCHAR2(7) TEMPORARY VARCHAR2(1) GENERATED VARCHAR2(1) SECONDARY VARCHAR2(1) 得到表中的列信息 mysql> show columns from columns_priv; +-------------+----------------------------------------------+------+-----+----- | Field | Type | Null | Key | Defa +-------------+----------------------------------------------+------+-----+----- | Host | char(60) | NO | PRI | | Db | char(64) | NO | PRI | | User | char(16) | NO | PRI | | Table_name | char(64) | NO | PRI | | Column_name | char(64) | NO | PRI | | Timestamp | timestamp | NO | | CURR | Column_priv | set('Select','Insert','Update','References') | NO | | +-------------+----------------------------------------------+------+-----+----- 7 rows in set (0.01 sec) +++ Oracle的实现方法 ++++ 通过user_tab_cols来实现。 SQL> select column_name from user_tab_cols where table_name='OFFER'; COLUMN_NAME ------------------------------ OWNER OBJECT_NAME SUBOBJECT_NAME OBJECT_ID DATA_OBJECT_ID OBJECT_TYPE CREATED LAST_DDL_TIME 得到索引的信息 mysql> show index from columns_priv; +--------------+------------+----------+--------------+-------------+----------- | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation +--------------+------------+----------+--------------+-------------+----------- | columns_priv | 0 | PRIMARY | 1 | Host | A | columns_priv | 0 | PRIMARY | 2 | Db | A | columns_priv | 0 | PRIMARY | 3 | User | A | columns_priv | 0 | PRIMARY | 4 | Table_name | A | columns_priv | 0 | PRIMARY | 5 | Column_name | A +--------------+------------+----------+--------------+-------------+----------- 5 rows in set (0.00 sec) +++ Oracle的实现方法 ++++ 通过User_indexes来实现 SQL> select index_name,index_type from user_indexes where table_name='OFFER'; INDEX_NAME INDEX_TYPE ------------------------------ --------------------------- INX_OFFER NORMAL 基于列的模糊查找 可能在这方面MySQL提供的直观方式要多一些。 mysql> show columns from columns_priv like '%ab%'; +------------+----------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +------------+----------+------+-----+---------+-------+ | Table_name | char(64) | NO | PRI | | | +------------+----------+------+-----+---------+-------+ 1 row in set (0.01 sec) +++ Oracle的实现方法 ++++ Oracle里面还是用user_tab_cols，一用倒底。 SQL> select column_name from user_tab_cols where table_name='OFFER' and column_name like '%OBJE%'; COLUMN_NAME ------------------------------ OBJECT_NAME SUBOBJECT_NAME OBJECT_ID DATA_OBJECT_ID OBJECT_TYPE 精确查找列名 mysql> show columns from columns_priv where field='User'; +-------+----------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+----------+------+-----+---------+-------+ | User | char(16) | NO | PRI | | | +-------+----------+------+-----+---------+-------+ 1 row in set (0.01 sec) +++ Oracle的实现方法 ++++ 还是使用usre_tab_cols，一用倒底。 SQL> select column_name from user_tab_cols where table_name='OFFER' and column_name= 'OBJECT_NAME'; COLUMN_NAME ------------------------------ OBJECT_NAME 查看进程相关的信息 mysql> show processlist -> ; +----+------+-----------------+-------+---------+------+-------+---------------- | Id | User | Host | db | Command | Time | State | Info +----+------+-----------------+-------+---------+------+-------+---------------- | 3 | root | localhost:49479 | mysql | Query | 0 | init | show processlis +----+------+-----------------+-------+---------+------+-------+---------------- 1 row in set (0.00 sec) +++ Oracle的实现方法 ++++ Oracle中提供了比较全面的视图，可以通过v$session,v$process来查找 USERNAME MACHINE PROGRAM SID ------------------------------ -------------------- ------------------------- ---------- REFWORK rac1 sqlplus@rac1 (TNS V1-V3) 257 select *from v$process; 查看数据字典的信息 MySQL中的数据字典信息都包含在schema information_schema里面 >mysqlshow information_schema Database: information_schema +---------------------------------------+ | Tables | +---------------------------------------+ | CHARACTER_SETS | | COLLATIONS | | COLLATION_CHARACTER_SET_APPLICABILITY | | COLUMNS | | COLUMN_PRIVILEGES | | ENGINES | | EVENTS | | FILES | | GLOBAL_STATUS | | GLOBAL_VARIABLES | | KEY_COLUMN_USAGE | | OPTIMIZER_TRACE | | PARAMETERS | | PARTITIONS | | PLUGINS | | PROCESSLIST | | PROFILING | | REFERENTIAL_CONSTRAINTS | | ROUTINES | +---------------------------------------+ +++ Oracle的实现方法 ++++ Oracle中的视图更加丰富，除了常说的数据字典表，还有动态性能视图，调优诊断很是方便。 select *from dict; --数据字典表 select *from v$fixed_table;--动态性能视图表