oracle常用命令(表、索引)

第三章：表

1.create a table
sql> create table table_name (column datatype,column datatype]....)
sql> tablespace tablespace_name [pctfree integer] [pctused integer]
sql> [initrans integer] [maxtrans integer]
sql> storage(initial 200k next 200k pctincrease 0 maxextents 50)
sql> [logging|nologging] [cache|nocache]
2.copy an existing table
sql> create table table_name [logging|nologging] as subquery
3.create temporary table
sql> create global temporary table xay_temp as select * from xay;
on commit preserve rows/on commit delete rows
4.pctfree = (average row size - initial row size) *100 /average row size
pctused = 100-pctfree- (average row size*100/available data space)
5.change storage and block utilization parameter
sql> alter table table_name pctfree=30 pctused=50 storage(next 500k
sql> minextents 2 maxextents 100);
6.manually allocating extents
sql> alter table table_name allocate extent(size 500k datafile 'c:/oracle/data.dbf');
7.move tablespace
sql> alter table employee move tablespace users;
8.deallocate of unused space
sql> alter table table_name deallocate unused [keep integer]
9.truncate a table
sql> truncate table table_name;
10.drop a table
sql> drop table table_name [cascade constraints];
11.drop a column
sql> alter table table_name drop column comments cascade constraints checkpoint 1000;
alter table table_name drop columns continue;
12.mark a column as unused
sql> alter table table_name set unused column comments cascade constraints;
alter table table_name drop unused columns checkpoint 1000;
alter table orders drop columns continue checkpoint 1000
data_dictionary : dba_unused_col_tabs

 

第四章：索引

1.creating function-based indexes
sql> create index summit.item_quantity on summit.item(quantity-quantity_shipped);
2.create a B-tree index
sql> create [unique] index index_name on table_name(column,.. asc/desc) tablespace
sql> tablespace_name [pctfree integer] [initrans integer] [maxtrans integer]
sql> [logging | nologging] [nosort] storage(initial 200k next 200k pctincrease 0
sql> maxextents 50);
3.pctfree(index)=(maximum number of rows-initial number of rows)*100/maximum number of rows
4.creating reverse key indexes
sql> create unique index xay_id on xay(a) reverse pctfree 30 storage(initial 200k
sql> next 200k pctincrease 0 maxextents 50) tablespace indx;
5.create bitmap index
sql> create bitmap index xay_id on xay(a) pctfree 30 storage( initial 200k next 200k
sql> pctincrease 0 maxextents 50) tablespace indx;
6.change storage parameter of index
sql> alter index xay_id storage (next 400k maxextents 100);
7.allocating index space
sql> alter index xay_id allocate extent(size 200k datafile 'c:/oracle/index.dbf');
8.alter index xay_id deallocate unused;