功能介绍
Oracle数据库在创建sequence的时候可以支持设置nomaxvalue，这样的SQL在LightDB 23.3版本之前都是执行失败的。为了方便Oracle用户迁移到LightDB上，在LightDB 23.3版本上，增加了sequence支持设置nomaxvalue的语法兼容。
nomaxvalue内部逻辑和PostgreSQL数据库sequence原本就支持的NO MAXVALUE相同。
使用说明
- 创建sequence时指定nomaxvalue
lightdb@lt_test=# create sequence s1 nomaxvalue;
CREATE SEQUENCE
lightdb@lt_test=# \d+ s1Sequence "public.s1"Type | Start | Minimum | Maximum | Increment | Cycles? | Cache
--------+-------+---------+---------------------+-----------+---------+-------bigint | 1 | 1 | 9223372036854775807 | 1 | no | 1lightdb@lt_test=#
- 修改sequence时指定nomaxvalue
lightdb@lt_test=# alter sequence s1 maxvalue 100000;
ALTER SEQUENCE
lightdb@lt_test=# \d+ s1Sequence "public.s1"Type | Start | Minimum | Maximum | Increment | Cycles? | Cache
--------+-------+---------+---------+-----------+---------+-------bigint | 1 | 1 | 100000 | 1 | no | 1lightdb@lt_test=# alter sequence s1 nomaxvalue;
ALTER SEQUENCE
lightdb@lt_test=# \d+ s1Sequence "public.s1"Type | Start | Minimum | Maximum | Increment | Cycles? | Cache
--------+-------+---------+---------------------+-----------+---------+-------bigint | 1 | 1 | 9223372036854775807 | 1 | no | 1lightdb@lt_test=#
- nomaxvalue不可以和no maxvalue或者maxvalue一起使用
lightdb@lt_test=# alter sequence s1 maxvalue 10000 nomaxvalue;
ERROR: conflicting or redundant options
LINE 1: alter sequence s1 maxvalue 10000 nomaxvalue;^
lightdb@lt_test=# alter sequence s1 no maxvalue nomaxvalue;
ERROR: conflicting or redundant options
LINE 1: alter sequence s1 no maxvalue nomaxvalue;^
lightdb@lt_test=#
