问题描述
我有一张这样的桌子
CONTACT
Name Null Type
------------------------------ -------- -----------
CONTACT_ID NOT NULL NUMBER
NAME NOT NULL VARCHAR2(45)
EMAIL NOT NULL VARCHAR2(45)
ADDRESS NOT NULL VARCHAR2(45)
TELEPHONE NOT NULL VARCHAR2(45)
AMOUNT NOT NULL FLOAT(126)
插入语句为:
Insert into contact("CONTACT_ID","NAME","EMAIL","ADDRESS","TELEPHONE","AMOUNT")
values ('36','babusailesh1117777','hainatu1@gmail.com','Vietnam1',
'0904277091','0.0000000555559080767');
当我看到插入数据库的最终值时，我看到了一个指数值.
When I see the final value inserted in the database, I see an exponential value.
如何在所有表的数据库级别避免这种情况?
How can I avoid this at database level for all tables?
推荐答案
它不是以指数形式存储的，而是以 Oracle 内部数字表示形式存储的.当您查询它时，它会以您会话的当前数字格式显示:
It isn't stored as an exponential, it's stored in Oracle's internal number representation. When you query it, it's displayed with your sessions's current number format:
select 0.0000000555559080767 from dual;
0.0000000555559080767
---------------------------------------
5.6E-08
您可以在 SQL*Plus 或 SQL Developer 中覆盖:
Which you can override in SQL*Plus or SQL Developer:
set numformat 999.9999999999999999999
select 0.0000000555559080767 from dual;
0.0000000555559080767
------------------------
.0000000555559080767
或将值显式格式化为字符串，仅用于显示:
Or explicitly format the value as a string, for display only:
set numf ""
select to_char(0.0000000555559080767, '9990.9999999999999999999') from dual;
TO_CHAR(0.000000055555908
-------------------------
0.0000000555559080767
如果您有一个客户端应用程序检索并使用该值，那么它应该将其作为浮点数查询，并转换为适合客户端语言的数据类型，然后由客户端决定如何显示.
If you have a client application retrieving and using the value then it should query it as a float, into a suitable data type for the client's language, and then it's up to the client how it's displayed.
您也不应该将字符串插入到浮点列中，这只是进行隐式转换；插入中的最后一个参数应该是 0.0000000555559080767 而不是引用的 '0.0000000555559080767'.
You also shouldn't be inserting a string into the float column, that just does an implicit conversion; the last argument in your insert should be 0.0000000555559080767 rather than the quoted '0.0000000555559080767'.
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