Entity framework with mysql database migrations fail, when creating indexes

Question

what causes this error in MySQL with entity framework? I can generate the migration script and connect to the database but it doesn't like the SQL generated particularly "hash" when trying to create indexes.

Example:

CREATE index  `IX_Facility_ID` on `Contact.Address` (`Facility_ID` DESC) using HASH

Error:

MySql.Data.MySqlClient.MySqlException (0x80004005): Incorrect usage of spatial/fulltext/hash index and explicit index order

Is there any way around this? This is with EF 6 and the latest mysql dlls.

Answer 1

i haved the same problem, after i read on posts, i decided create a class inherits ofMySqlMigrationSqlGenerator and override protected override MigrationStatement Generate ( CreateIndexOperation op ), then on configuration of migration i add : SetSqlGenerator ( "MySql.Data.MySqlClient", new myMigrationSQLGenerator ( ) );

this is the code of class:

public class myMigrationSQLGenerator : MySqlMigrationSqlGenerator
{
    private string TrimSchemaPrefix ( string table )
    {
        if ( table.StartsWith ( "dbo." ) )
            return table.Replace ( "dbo.", "" );
        return table;
    }

    protected override MigrationStatement Generate ( CreateIndexOperation op )
    {
        var u = new MigrationStatement ( );
        string unique = ( op.IsUnique ? "UNIQUE" : "" ), columns = "";
        foreach ( var col in op.Columns )
        {
            columns += ( $"`{col}` DESC{( op.Columns.IndexOf ( col ) < op.Columns.Count - 1 ? ", " : "" )}" );
        }
        u.Sql = $"CREATE {unique} INDEX `{op.Name}` ON `{TrimSchemaPrefix ( op.Table )}` ({columns}) USING BTREE";
        return u;
    }
}

and this is the code on Migrations\Configuration.cs:

    public Configuration ()
    {           
        AutomaticMigrationsEnabled = false;
        SetSqlGenerator ( "MySql.Data.MySqlClient", new myMigrationSQLGenerator ( ) );
    }

this work for me.

Answer 2

Looking the MySql source code, you need to add this(anonymousArguments: new { Type = "BTrees" }) on index definitions:

.Index(t => t.GroupId, anonymousArguments: new { Type = "BTrees" });

This is not a fix, but for the moment you can apply the migration code.