Oracle 查看表结构

一直以来对，PLSQL里的查看表结构念念，想通过SQL实现。但是默认值是Long类型，取不出字符。终于今天想到了一个方法。这个语句只能查询当前用户的表结构，可用于写文档时，直接复制到文档里。

CREATE OR REPLACE fUNCTION GET_Datadefault(in_table_name varchar,
in_column varchar2)
RETURN varchar AS
text_c1 varchar2(32767);
sql_cur varchar2(2000);
begin
sql_cur := 'select Data_default ' ||
' from user_tab_columns ' ||
' where column_name =' || chr(39) || in_column || chr(39) ||
' and Table_Name=' || chr(39) || in_table_name || chr(39);
dbms_output.put_line(sql_cur);
execute immediate sql_cur
into text_c1;

text_c1 := substr(text_c1, 1, 4000);
RETURN TEXT_C1;
END;

--查询表结构
select A.column_name 名称,
Case
When a.Data_Type = 'VARCHAR2' Then
'VARCHAR2(' || a.Data_Length || ')'
When a.Data_Type = 'NUMBER' and A.Data_Scale = 0 Then
'INTEGER'
When a.Data_Type = 'NUMBER' and A.data_precision > 0 Then
'NUMBER(' || a.data_precision || ',' || A.Data_Scale || ')'
Else
a.Data_Type
End 类型,
decode(A.nullable, 'Y', 'Y', '') 可为空,
GET_Datadefault(A.Table_Name, a.COLUMN_NAME) 默认,
B.comments 注释,
(Select 'Y'
From User_Constraints Con, User_Cons_Columns Col
Where Con.Constraint_Name = Col.Constraint_Name
And Con.Constraint_Type = 'P'
And Col.Column_Name = a.Column_Name
And Col.Table_Name = a.Table_Name) 主键
from user_tab_columns A, user_col_comments B
where a.COLUMN_NAME = b.column_name
and A.Table_Name = B.Table_Name
and A.Table_Name = 'FREIGHT_PRICE_RANGE'--表名
order by A.COLUMN_ID