Postgresql/openJPA (geronimo) 序列问题
我在序列方面遇到了一个奇怪的问题。我使用 postgresql 9 和 geronimo 2.2。我已经在数据库环境中创建了序列 PLANTS_ID_SEQ ，当我尝试创建新实体时，我在日志中收到错误（来自 postegresql），关系 PLANTS_ID_SEQ存在。它似乎试图创建已经创建的序列。这是来自实体 bean 的代码：
@Id
@GeneratedValue(generator="PLANTS_SEQ",strategy=GenerationType.SEQUENCE) @SequenceGenerator(name="PLANTS_SEQ", sequenceName="PLANTS_ID_SEQ",allocationSize=1) @Column(name = "ID")
private Integer id;
请注意，如果我更改序列名称（例如sequenceName="MY_SEQ"），那么代码会正确运行，但它会在 postgresql 中创建（并且显然使用）MY_SEQ顺序。如果有人对此案有任何线索，请分享。 谢谢乔治
I am having a weird problem with a sequence. Im using postgresql 9 with geronimo 2.2. I have created the sequence PLANTS_ID_SEQ inside the db environment and when I try to create a new entity I get an error in my logs (which comes from postegresql) that the relation PLANTS_ID_SEQ exists. It seems that it tries to create the sequence that is already created. This is the code from the entity bean:
@Id
@GeneratedValue(generator="PLANTS_SEQ",strategy=GenerationType.SEQUENCE) @SequenceGenerator(name="PLANTS_SEQ", sequenceName="PLANTS_ID_SEQ",allocationSize=1) @Column(name = "ID")
private Integer id;
Please notice that if I change the sequence name (eg sequenceName="MY_SEQ")then the code runs correctly but it creates in postgresql (and obviously uses) the MY_SEQ sequence. If anyone has a clue about this case please share.
Thanks George
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如果你的表有一个 SERIAL 类型的列，那么 postgres 将为你创建序列并在插入时自动使用它。
它创建的序列被命名为“tablename_id_seq”...
可能您正在尝试复制 postgres 已经完成的操作，并创建一个重复的序列。
If your table has a column of type SERIAL, then postgres will create the sequence for you and use it automatically on inserts.
The sequence it creates is named "tablename_id_seq"...
Probably you're trying to duplicate what postgres has already done, and create a duplicate sequence.
已解决：
应在 persistence.xml 中添加以下属性：
这样，openjpa 的 MappingTool 就不会尝试再次创建序列。
Solved:
Should add in persistence.xml the following property:
this way, the MappingTool of openjpa will not try to create the sequence again.