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HomeDatabaseMysql TutorialOracle数据库查询表的基本信息

因为Oracle项目某些模块的数据结构设计没有严格按照某规范设计,所以只能从数据库中查询数据结构,需要查询的信息如下:字段

    因为Oracle项目某些模块的数据结构设计没有严格按照某规范设计,所以只能从数据库中查询数据结构,需要查询的信息如下:字段名称、数据类型、是否为空、默认值、主键、外键等等。

    在网上搜索了查询上述信息的方法,总结如下:

    一,查询表基本信息

    select

    utc.column_name,utc.data_type,utc.data_length,utc.data_precision, utc.data_Scale,utc.nullable,utc.data_default,ucc.comments

    from

    user_tab_columns utc,user_col_comments ucc

    where

    utc.table_name = ucc.table_name and utc.column_name = ucc.column_name and utc.table_name = 'ONLINEXLS'

    order by

    column_id

    注意:order by column_id的意义是使得结果按照设计数据结构时的顺序显示。

    二,查询表主键

    select

    col.column_name

    from

    user_constraints con,user_cons_columns col

    where

    con.constraint_name=col.constraint_name and con.constraint_type='P' and col.table_name='ONLINEXLS'三,查询表外键

    select

    distinct(ucc.column_name) column_name,rela.table_name,rela.column_name column_name1

    from

    user_constraints uc,user_cons_columns ucc, (select t2.table_name,t2.column_name,t1.r_constraint_name from user_constraints t1,user_cons_columns t2 where t1.r_constraint_name=t2.constraint_name and t1.table_name='ONLINEXLS') rela

    where

    uc.constraint_name=ucc.constraint_name and uc.r_constraint_name=rela.r_constraint_name and uc.table_name='ONLINEXLS'

    1、查找表的所有索引(包括索引名,类型,构成列):

    select t.*,i.index_type from user_ind_columns t,user_indexes i where t.index_name = i.index_name and t.table_name = i.table_name and t.table_name = 要查询的表

    2、查找表的主键(包括名称,构成列)表名大写 :

    select cu.* from user_cons_columns cu, user_constraints au where cu.constraint_name = au.constraint_name and au.constraint_type = 'P' and au.table_name = '要查询的表' ;

    仅查询表主键

    select column_name from user_cons_columns wherE CONSTRAINT_NAME in (select CONSTRAINT_NAME from user_constraints where table_name =upper('表名') and CONSTRAINT_TYPE='P');

    3、查找表的唯一性约束(包括名称,构成列):

    select column_name from user_cons_columns cu, user_constraints au where cu.constraint_name = au.constraint_name and au.constraint_type = 'U' and au.table_name = 要查询的表

    4、查找表的外键(包括名称,,引用表的表名和对应的键名,下面是分成多步查询):

    select * from user_constraints c where c.constraint_type = 'R' and c.table_name = 要查询的表

    查询外键约束的列名:

    select * from user_cons_columns cl where cl.constraint_name = 外键名称

    查询引用表的键的列名:

    select * from user_cons_columns cl where cl.constraint_name = 外键引用表的键名

    5、查询表的所有列及其属性

    select t.*,c.COMMENTS from user_tab_columns t,user_col_comments c where t.table_name = c.table_name and t.column_name = c.column_name and t.table_name = 要查询的

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