使用unaccent使用Npgsql和Entity Framework查询PostgreSQL [英] Query PostgreSQL with Npgsql and Entity Framework using unaccent
问题描述
是否可以使用Npgsql和Entity Framework 6来查询PostgreSQL而忽略重音符号?在运行SQL时,可以使用unaccent扩展名,并可以使用基于unaccent的索引进行索引:
Is possible to use Npgsql and Entity Framework 6 for query PostgreSQL ignoring accents? In play SQL it's possible to use the unaccent extension and could be indexed with a index also based in unaccent:
select * from users where unaccent(name) = unaccent('João')
在以前使用MySql的项目中,我可以解决此问题仅使用诸如utf8_swedish_ci之类的排序规则重音不敏感的问题,但据我所知PostgreSQL缺少这种解决方案。
In previous projects using MySql I could solve this problem just using a collation accent insensitive like utf8_swedish_ci but PostgreSQL lacks this kind of solution as far as I know.
推荐答案
如果使用 Codefirst 方法,则应尝试使用 EntityFramework.CodeFirstStoreFunctions 。
If you use the Codefirst approach, you should try to use EntityFramework.CodeFirstStoreFunctions.
- First将EntityFramework.CodeFirstStoreFunctions添加到您的项目
- 将带有 unaccent 的自定义约定添加到DbModelBuilder
- 在查询中使用它。
- First add EntityFramework.CodeFirstStoreFunctions to your project
- Add a custom convention with unaccent to DbModelBuilder
- Use it in a query.
数据库上下文示例:
public class DatabaseContext : DbContext
{
public DatabaseContext () : base("Context")
{
Database.SetInitializer<DatabaseContext>(null);
}
public DbSet<User> Users { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.HasDefaultSchema("public");
modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
/** Adding unaccent **/
modelBuilder.Conventions.Add(new CodeFirstStoreFunctions.FunctionsConvention<DatabaseContext>("public"));
}
[DbFunction("CodeFirstDatabaseSchema", "unaccent")]
public string Unaccent(string value)
{
// no need to provide an implementation
throw new NotSupportedException();
}
}
用法示例:
var users = ctx.Users
.Where(elem => ctx.Unaccent(elem.FirstName) == ctx.Unaccent("João"))
.ToList();
重要提示:
此解决方案与 EntityFramework6.Npgsql (使用Npgsql 3. *)。
不适用于 Npgsql.EntityFramework (使用Npgsql 2。*)
Important notice:
This solution works with EntityFramework6.Npgsql (which uses Npgsql 3.*).
It doesn't work with Npgsql.EntityFramework (which uses Npgsql 2.*)
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