public enum UniqueIndexNulls extends java.lang.Enum
How the unique index Hibernate creates over nullable columns treats a null in the key, by database. This is one fact about each database, and everything that has to agree with the index asks it here:
('en', null) twice is a violation, and only a key that is null in every column is left out.
Oracle indexes that way. On Db2 for Linux, UNIX and Windows Hibernate creates the index with
exclude null keys: a unique index treats a null as any other value, and exclude null keys leaves out
only a key that is null in every column, which comes to the same.create unique where not null index, under which nulls are not equal to each other.| Type Params | Return Type | Name and description |
|---|---|---|
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public java.lang.Class<? extends org.hibernate.dialect.Dialect>[] |
dialectClasses() |
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public static UniqueIndexNulls |
forDialect(org.hibernate.dialect.Dialect dialect)Returns how the unique index of the database the dialect is for treats a null in its key. |
| Methods inherited from class | Name |
|---|---|
class java.lang.Enum |
java.lang.Enum#compareTo(java.lang.Enum), java.lang.Enum#compareTo(java.lang.Object), java.lang.Enum#describeConstable(), java.lang.Enum#equals(java.lang.Object), java.lang.Enum#getClass(), java.lang.Enum#getDeclaringClass(), java.lang.Enum#hashCode(), java.lang.Enum#name(), java.lang.Enum#notify(), java.lang.Enum#notifyAll(), java.lang.Enum#ordinal(), java.lang.Enum#toString(), java.lang.Enum#valueOf(java.lang.Class, java.lang.String), java.lang.Enum#wait(), java.lang.Enum#wait(long), java.lang.Enum#wait(long, int) |
Returns how the unique index of the database the dialect is for treats a null in its key.