searching for the same.. Did u get any solution??

We are using nvarchar(4000) for now, but we thought of doing an "alter table" after the PetaPoco table creation as we cannot create a nvarchar(max) column.

Just did a quick test. The alter table workaround works.

db.Execute("ALTER TABLE Test ALTER COLUMN Description NVARCHAR(MAX)");

I know this post is old but I thought I post the easier way:

Decorate the class as follows:

    [Column("properties")]
    [Length(4000)]
    public string properties { set; get; }

Does the same as nvarcharMAX

I develop a little code to adjust table after creation.
It convert any column of table where datatype is NVARCHAR(3999) in NVARCHAR(MAX).
Instead of convert NTEXT, I choose to search and convert NVACHAR because PetaPoco need to know the real dbType.
The length 3999 is a "key-value" to activate the conversion. So the 4000 size is free to use when necessary.

public const int NVarcharMaxSizeKey = 3999;

private void adjustNVarcharMaxFields(DatabaseContext dbContext, System.Type modelDtoType)
{
    var sqlSyntaxProvider = ApplicationContext.Current.DatabaseContext.SqlSyntax;
    var sqlParts = new List<string>();

    var tableNameAttribute = modelDtoType.FirstAttribute<TableNameAttribute>();
    var tableName = tableNameAttribute.Value;

    var objProperties = modelDtoType.GetProperties().ToList();

    foreach (var propertyInfo in objProperties)
    {
        //If current property has an IgnoreAttribute then skip it
        var ignoreAttribute = propertyInfo.FirstAttribute<IgnoreAttribute>();
        if (ignoreAttribute != null) continue;

        //If current property has a ResultColumnAttribute then skip it
        var resultColumnAttribute = propertyInfo.FirstAttribute<ResultColumnAttribute>();
        if (resultColumnAttribute != null) continue;

        //Looks for ColumnAttribute with the name of the column, which would exist with ExplicitColumns
        //Otherwise use the name of the property itself as the default convention
        var columnAttribute = propertyInfo.FirstAttribute<ColumnAttribute>();
        string columnName = columnAttribute != null ? columnAttribute.Name : propertyInfo.Name;

        // Filtering for column where `SpecialDbTypeAttribute` attribute is not defined (or NVARCHAR value).
        var sqlColumnTypeAttribute = propertyInfo.FirstAttribute<SpecialDbTypeAttribute>();
        if (sqlColumnTypeAttribute != null) continue;

        // Filtering for column where `LengthAttribute` is 3999.
        var lengthAttribute = propertyInfo.FirstAttribute<LengthAttribute>();
        if (lengthAttribute == null || lengthAttribute.Length != NVarcharMaxSizeKey) continue;

        // Reading nullable column property.
        var nullSettingAttribute = propertyInfo.FirstAttribute<NullSettingAttribute>();
        var nullableColumn = nullSettingAttribute != null && nullSettingAttribute.NullSetting == NullSettings.Null;

        // Compiling SQL COMMAND for ALTER COLUMN
        sqlParts.Add(string.Format(sqlSyntaxProvider.AlterColumn,
            sqlSyntaxProvider.GetQuotedTableName(tableName),
            string.Format("{0} NVARCHAR(MAX) {1}NULL", columnName, (nullableColumn ? "" : "NOT "))
            ));
    }

    // Executing
    if (sqlParts.Count > 0)
    {
        var sql = string.Join("\r\n", sqlParts);

        dbContext.Database.Execute(sql);
    }
}

Hi Guys,

I do a similar kind of thing as a couple of people above.

My Model/Poco field looks something like this.

[Column("Body")]

public string Body { get; set; }

So by default this would get inserted as NVARCHAR(255)

I then run an update on that column straight after the migration. Here is an example of my Composition initialize method which I usually add this into.

public class MigrationPlanComponent : IComponent
    {
        private readonly IScopeProvider _scopeProvider;
        private readonly IMigrationBuilder _migrationBuilder;
        private readonly IKeyValueService _keyValueService;
        private readonly ILogger _logger;

        public MigrationPlanComponent(IScopeProvider scopeProvider,IMigrationBuilder migrationBuilder,IKeyValueService keyValueService,ILogger logger)
        {
            _scopeProvider = scopeProvider;
            _migrationBuilder = migrationBuilder;
            _keyValueService = keyValueService;
            _logger = logger;
        }

        public void Initialize()
        {
            var upgrader = new Upgrader(new UMB8SMMMigrationPlan());
            upgrader.Execute(_scopeProvider, _migrationBuilder, _keyValueService, _logger);

            using (var scope = _scopeProvider.CreateScope())
            {
                scope.Database.Execute("ALTER TABLE UMB8SMMEmailQueue ALTER COLUMN Body NVARCHAR(MAX)");
                scope.Complete();
            }
        }

        public void Terminate()
        {
            throw new NotImplementedException();
        }
    }

Once this is complete the column is updated to NVARCHAR(MAX) as desired.

Hope this helps someone.

Regards David

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