JPA: how to map SQL Server uniqueidentifier type
hibernate, java, sql-server
Solution
The data type of the primary key property in the POJO determines the data type of its mapped DB column, which is specified by the Dialect class. According to the SQLServerDialect provided by hibernate, it does not have any data type that maps to `uniqueidentifier`, and `String` by default maps to `varchar(255)`
I think `guid` strategy on a `String` primary key only means that hibernate will generate a GUID value for POJO's primary key property and this generated GUID value will be inserted to the `varchar(255)` column to simulate the effect of `uniqueidentifier`
You can try to override the mapping specified by the Dialect class by using the columnDefinition attribute of `@Column`
@Id
@GenericGenerator(name = "generator", strategy = "guid", parameters = {})
@GeneratedValue(generator = "generator")
@Column(name = "APPLICATION_ID" , columnDefinition="uniqueidentifier")
private String id;
Problem
I've inherited a SQL Server database that I'm trying to map via JPA. Many of the tables have a `uniqueidentifier` column. I'm trying to map them like so: ``` @Id @GenericGenerator(name = "generator", strategy = "guid", parameters = {}) @GeneratedValue(generator = "generator") @Column(name = "APPLICATION_ID") private String id; ``` Hibernate complains with: ``` Found: uniqueidentifier, expected: varchar(255) ```