Obtain database type in fluent syntax

[rhegner]

Obtain database type in fluent syntax

[fubar-coder]

This is what I did when I needed to support a "JSON" column, but it should be usable for your situation too: I created a custom IColumnsConvention.

Example:

class MyCustomColumnConvention : IColumnsConvention {
  private readonly string _databaseType;

  public MyCustomColumnConvention(IProcessorAccessor processorAccessor) {
    _databaseType = processorAccessor.Processor.DatabaseType.ToLowerInvariant();
  }

  public IColumnsExpression Apply(IColumnsExpression expression) {
    var jsonColumns = expression.Columns
      .Where(x => string.Equals("json", x.CustomType, StringComparison.OrdinalIgnoreCase))
      .ToList();
    if (jsonColumns.Count == 0) {
      return expression;
    }

    if (_databaseType == "sqlserver2016") {
      foreach (var column in jsonColumns) {
        column.CustomType = null;
        column.Type = DbType.String;
        column.Size = int.MaxValue;
      }
    }

    return expression;
  }
}

[schambers]

Do you think your comment would be useful in the documentation @fubar-coder? I can create an issue to add this example there. This is a good work around it seems.

[fubar-coder]

Yes, it might be a good idea, but a full example is needed to be a usable example, which requires either:

• Querying the scoped IConventionSet service and add your own IColumnsConvention the the set
• A custom IConventionSet as scoped service, which should be derived from DefaultConventionSet, have only one public constructor, and the custom IColumnsConvention must be added to the ColumnsConventions property

The first one works better when the developer relies on behavior of the IConventionSetAccessor implementation (AssemblySourceConventionSetAccessor), while the second is better if you prefer not to rely on assembly scanning.

[schambers]

How does this look @fubar-coder, I'm unsure of option 2 and was contemplating leaving it as it appears but open to suggestions: fluentmigrator/documentation@7082a13

[jzabroski]

Duplicate of #1032

[schambers]

I'll close this as I have an issue on the documentation repo to cover this documnetation: fluentmigrator/documentation#75

We could move any discussion there