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我在postgresql数据库中查询需要太多的时间,我喜欢添加一个索引使其更快,但我不知道哪些字段shouls我包含在索引中,因为它们中的许多属于其他表和其中一些是外键。哪些字段应该放在索引中?
我使用Hibernate和HQL查询是这个:从它看起来像一个我下面包括模型自动生成
SELECT i FROM Item i
LEFT JOIN i.model.kind AS k
LEFT JOIN i.model.kind.subkind AS s
WHERE i.file is null " +
AND i.identifier is not null
AND i.identifier != ''
AND i.place is not null
AND i.place.id = :placeId
AND (upper(i.serial) LIKE upper(:keyword)
OR upper(i.code) LIKE upper(:keyword)
OR upper(i.law.law) LIKE upper(:keyword)
OR upper(i.model.model) LIKE upper(:keyword)
OR upper(k.kind) LIKE upper(:keyword)
OR upper(s.subkind) LIKE upper(:keyword)
OR upper(i.model.factory.factory) LIKE upper(:keyword)
)
ORDER BY i.code, i.id
数据库的架构。
哪些字段会在索引中包含?
谢谢。
public class Item {
@Id
private Long id;
private String identifier;
private String code;
private String serial;
@ManyToOne
private File file;
@ManyToOne
private Law law;
@ManyToOne
private Place place;
@ManyToOne
private Model model;
}
public class File {
@Id
private Long id;
private String file;
}
public class Law {
@Id
private Long id;
private String law;
}
public class Place {
@Id
private Long id;
private String place;
}
public class Model {
@Id
private Long id;
private String model;
@ManyToOne
private Factory factory;
@ManyToOne
private Kind kind;
}
public class Factory {
@Id
private Long id;
private String factory;
}
public class Kind {
@Id
private Long id;
private String kind;
@ManyToOne
private Subkind subkind;
}
public class Subkind {
@Id
private Long id;
private String subkind;
}
什么你想要做的是使用一个索引更适合于Lucene,几乎不可能优化传统的DBMS索引以处理大量文本搜索和或子句......您将始终需要扫描所有索引的全部内容。 – Mainguy 2012-07-11 14:31:15