Oracle性能调优：OracleDDL,DML,DCL，TCL总结

会计考友

Oracle DDL,DML,DCL,TCL总结
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    前段时间的浮躁，总觉得这也会，那也会，但是清醒过来发现自己什么都不会，连基本概念都不知道，还是从头来一遍吧，踏踏实实的学习一段时间。
   
    把oracle学习来可以独挡一面的实施，维护，当然优化是一个很漫长的岁月炼就的经验之谈，需要多积累经验。
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    下面是一些网上找的资料，自己总结到一起。
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/ [5 R" C; t8 u! G' d/ x& z    一般sql语言增删改查和alter,比较常用，oracle里面commit和revoke比较常用，这些对于我来说很迷糊，希望自己踏实下去。
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    DDL
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6 v4 R3 ~  c: L  [    Data Definition Language （DDL） statements are used to define the database structure or schema. Some examples:
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% X1 V* ^5 ]8 F& G) c    CREATE - to create objects in the database
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    ALTER - alters the structure of the database
   
4 h; A! j2 Y7 W& @; x+ {    DROP - delete objects from the database
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    TRUNCATE - remove all records from a table, including all spaces allocated for the records are removed
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    COMMENT - add comments to the data dictionary
   
    RENAME - rename an object
   
0 H* K5 l! X! g    DML
   
    Data Manipulation Language （DML） statements are used for managing data within schema objects. Some examples:
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    SELECT - retrieve data from the a database
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! `- P7 B) K, W+ V; O9 M    INSERT - insert data into a table
   
: o$ l' e/ m! a7 J; K( f/ q- F    UPDATE - updates existing data within a table
   
    DELETE - deletes all records from a table, the space for the records remain
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4 d; y( b5 S5 G9 l2 u/ n$ X    MERGE - UPSERT operation （insert or update）
   
    CALL - call a PL/SQL or Java subprogram
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& w+ ~) j( n: C8 c/ ~    EXPLAIN PLAN - explain access path to data
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: ]( I# I: O* p$ d% i    LOCK TABLE - control concurrency
   
/ p7 u: {5 _+ i9 W$ A    DCL
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    Data Control Language （DCL） statements. Some examples:
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3 p- G, Z$ f1 g5 M) o3 r, a* w    GRANT - gives user's access privileges to database
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/ O+ Y: U# B5 p7 s    REVOKE - withdraw access privileges given with the GRANT command
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    TCL
   
    Transaction Control （TCL） statements are used to manage the changes made by DML statements. It allows statements to be grouped together into logical transactions.
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    COMMIT - save work done
   
0 M- x5 p, |. U- ?4 _4 ]    SAVEPOINT - identify a point in a transaction to which you can later roll back
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    ROLLBACK - restore database to original since the last COMMIT
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5 _- Z) a- `0 p, p0 |    SET TRANSACTION - Change transaction options like isolation level and what rollback segment to use
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1 B9 Z9 i7 M* x* D2 x    上面的比较官方，下面自己的理解和大多数人通俗易懂的形式。