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一.sql语句
1.增加主键
alter table TABLE_NAME add constraint KEY_NAME primary key (TABLE_COLUMN);
指定表空间
alter table TABLE_NAME add constraint KEY_NAME primary key (TABLE_COLUMN) using index tablespace TABLE_SPACE_NAME;
2.增加外键
alter table TABLE_NAME add constraint FK_NAME foreign key (TABLE_COLUMN) references KEY_TABLE_NAME;
3.使主键或外键失效、生效
alter table TABLE_NAME disable(enable) constraint KEY_NAME;
4、查看各种约束
select constraint_name,table_name,constraint_type,status from user_constraints;
select constraint_name, constraint_type,search_condition, r_constraint_name from user_constraints where table_name = upper('&table_name')
select c.constraint_name,c.constraint_type,cc.column_name
from user_constraints c,user_cons_columns cc
where c.owner = upper('&table_owner') and c.table_name = upper('&table_name')
and c.owner = cc.owner and c.constraint_name = cc.constraint_name
order by cc.position;
5、删除主键或外键
alter table TABLE_NAME drop constraint KEY_NAME;
6、建外键
单字段时：create table 表名 (col1 char(8),
cno char(4) REFERENCE course);
多个字段时,在最后加上 Foreign Key (字段名) REFERENCE 表名(字段)
连带删除选项 (on delete cascade
当指定时，如果父表中的记录被删除，则依赖于父表的记录也被删除
REFERENCE 表名（） on delete cascade;
7、删除带约束的表
Drop table 表名 cascade constraints;
8：索引管理
<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
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