Quick and dirty VARCHAR(MAX) implementation for Ormlite's SQL Server provider. Any property marked with [StringLength(<value>)] is created as a VARCHAR(MAX) column when <value> exceeds 8000

MySqlServerOrmLiteDialectProvider.cs

public class MySqlServerOrmLiteDialectProvider :
        SqlServerOrmLiteDialectProvider
    {
        public static new MySqlServerOrmLiteDialectProvider Instance = new MySqlServerOrmLiteDialectProvider();

        public override string GetColumnDefinition(string fieldName, Type fieldType, bool isPrimaryKey, bool autoIncrement, bool isNullable, int? fieldLength, int? scale, string defaultValue)
        {
            string fieldDefinition;

            // Begin: Override edit
            if (fieldType == typeof(string))
            {
                string colLength = null;
                var intVal = fieldLength.GetValueOrDefault(DefaultStringLength);
                
                // SQL Server max int value for varchar datatype is 8000.  
                // So move up to the MAX option if > 8000
                if (intVal > 8000)
                    colLength = "MAX";
                else
                    colLength = intVal.ToString();

                fieldDefinition = string.Format(StringLengthColumnDefinitionFormat, colLength);
            }
            // End: Override edit
            else
            {
                if (!DbTypes.ColumnTypeMap.TryGetValue(fieldType, out fieldDefinition))
                {
                    fieldDefinition = this.GetUndefinedColumnDefinition(fieldType, fieldLength);
                }
            }

            var sql = new StringBuilder();
            sql.AppendFormat("{0} {1}", GetQuotedColumnName(fieldName), fieldDefinition);

            if (isPrimaryKey)
            {
                sql.Append(" PRIMARY KEY");
                if (autoIncrement)
                {
                    sql.Append(" ").Append(AutoIncrementDefinition);
                }
            }
            else
            {
                if (isNullable)
                {
                    sql.Append(" NULL");
                }
                else
                {
                    sql.Append(" NOT NULL");
                }
            }

            if (!string.IsNullOrEmpty(defaultValue))
            {
                sql.AppendFormat(DefaultValueFormat, defaultValue);
            }

            return sql.ToString();
        }
    }

That's really confusing to see MySql! Had to read this like 8 times to realize it was indeed SqlServer.

Shorter implementation is:

public override string GetColumnDefinition(string fieldName, Type fieldType, bool isPrimaryKey,
    bool autoIncrement, bool isNullable, int? fieldLength, int? scale, string defaultValue)
{
    var fieldDefinition = base.GetColumnDefinition(fieldName, fieldType, isPrimaryKey, 
                                  autoIncrement, isNullable, fieldLength, scale, defaultValue);

    if (fieldType == typeof (string) && fieldLength > 8000)
    {
        var orig = string.Format(StringLengthColumnDefinitionFormat, fieldLength);
        var max = string.Format(StringLengthColumnDefinitionFormat, "MAX");

        fieldDefinition = fieldDefinition.Replace(orig, max);
    }

    return fieldDefinition;
}