在sybase中使用auto_increment主键创建表，截断表后主键不为零答案

【问题标题】：create table in sybase with auto_increment primary key,after truncate the table the primary key is not zero在sybase中使用auto_increment主键创建表，截断表后主键不为零
【发布时间】：2019-01-01 18:20:36
【问题描述】：

我使用下面的SQL创建了一个带有auto_increment主键的表，但是在截断表后发现主键没有重置为零，因为在向它插入数据后，主键从上次截断后继续增加。我相信初级会太大而导致溢出。如何解决？

CREATE TABLE dbo.BM_SM_ERR
(
    SMCWBM int          identity,   -- primary key
    SMCWDM varchar(10)  NOT NULL,   
    PRIMARY KEY CLUSTERED (SMCWBM)
)
with identity_gap=1

sybase 版本 Adaptive Server Enterprise 15.7

【问题讨论】：

标签： primary-key sybase sybase-ase15

【解决方案1】：

在删除、截断表或关闭后，标识不会重置。如果你想用sp_chgattribute 过程手动重置它：

1> insert into BM_SM_ERR(SMCWDM) values ('x')
2> go
(1 row affected)
1> insert into BM_SM_ERR(SMCWDM) values ('y')
2> go
(1 row affected)
1> insert into BM_SM_ERR(SMCWDM) values ('z')
2> go
(1 row affected)
1> select * from BM_SM_ERR
2> go
 SMCWBM      SMCWDM     
 ----------- ---------- 
           1 x          
           2 y          
           3 z          

(3 rows affected)
1> truncate table BM_SM_ERR
2> go
1> insert into BM_SM_ERR(SMCWDM) values ('v')
2> go
(1 row affected)
1> select * from BM_SM_ERR
2> go
 SMCWBM      SMCWDM     
 ----------- ---------- 
           4 v          

(1 row affected)
1> truncate table BM_SM_ERR
2> go
1> exec sp_chgattribute BM_SM_ERR, 'identity_burn_max', 0, '0'
2> go
DBCC execution completed. If DBCC printed error messages, contact a user with System Administrator (SA) role.
'identity_burn_max' attribute of object 'BM_SM_ERR' changed to 0.
(return status = 0)
1> insert into BM_SM_ERR(SMCWDM) values ('q')
2> go
(1 row affected)
1> select * from BM_SM_ERR
2> go
 SMCWBM      SMCWDM     
 ----------- ---------- 
           1 q          

(1 row affected)

【讨论】：