oracle oracle中如何判断一列是否为自增字段？
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How to find out if a column is an auto increment field in oracle?
提问by nakiya
How to find out if a column is an auto increment field in oracle?
oracle中如何判断一列是否为自增字段？
回答by GolezTrol
You can't. Oracle doesn't have auto-increment fields.
你不能。Oracle 没有自动增量字段。
Oracle supports sequences, which are separate database objects for generating numbers. These seuqences can be used in the insert statement or in a before insert trigger to generate a primary key value for the new record.
Oracle 支持序列，它们是用于生成数字的独立数据库对象。这些序列可以在插入语句或插入前触发器中使用，以生成新记录的主键值。
The fields themselves are just normal field and there is no relation between the sequence and the field.
字段本身只是普通字段，序列和字段之间没有关系。
So the only hope is to parse a trigger and see if you can find evidence of it being filled there using a sequence. That would be a tough job, though, and I doubt if you can make this reliable enough. After all, the trigger could fire a function which returns the value, so you have to go all the way if you want to be sure.
所以唯一的希望是解析一个触发器，看看是否可以找到使用序列填充它的证据。不过，这将是一项艰巨的工作，我怀疑您是否能让它足够可靠。毕竟，触发器可以触发一个返回值的函数，所以如果你想确定的话，你必须一路走下去。
回答by user3861225
As of Oracle 12.1 identity columns (with self generated sequences) can be identified by looking at the "DATA_DEFAULT" column of view DBA_TAB_COLUMS (or USER_TAB_COLUMNS or ALL_TAB_COLUMNS). They will look like "#OWNER"."ISEQ$$_nnnnn".nextval
从 Oracle 12.1 开始，可以通过查看视图 DBA_TAB_COLUMS（或 USER_TAB_COLUMNS 或 ALL_TAB_COLUMNS）的“DATA_DEFAULT”列来识别身份列（带有自生成的序列）。它们看起来像 "#OWNER"."ISEQ$$_nnnnn".nextval
