datatypes | GORM Customized Data Types Collection | JSON Processing library

Is there something like Show (deriving Show) that only uses an algebraic datatype's constructors? (please don't mind that I'm using the word constructor, I don't know the right name...)

The reason for this question is that with many of my algebraic datatypes I don't want to bother with making their contents also derive Show, but I still want to gain some debug information about the constructor used without having to implement showing every constructor...

An alternative could be a function that gives me the constructors name, that I can use in my own implementation of show.

This of course needs to do some compiler magic (auto deriving) because the whole idea behind is to not have to explicitely implement every data constructors string representation.

I'm just getting into BIML and have written some Scripts to creat a few DTSX-Packages. In general the most things are working. But one thing makes me crazy.

I have an ODBC-Source (PostgreSQL). From there I'm getting data out of a table using an ODBC-Source. The table has a text-Column (Name of the column is "description"). I cast this column to varchar(4000) in the query in the ODBC-Source (I know that there will be truncation, but it's ok). If I do this manually in Visual Studio the Advanced Editor of the ODBC-Source is showing "Unicode string [DT_WSTR]" with a Length of 4000 both for the External and the Output-Column. So there everything is fine. But if I do the same things with BIML and generate the SSIS-Package the External-Column will still say "Unicode string [DT_WSTR]" with a Length of 4000, but the Output-Column is telling "Unicode text stream [DT_NTEXT]". So the mapping done by BIML differs from the Mapping done by SSIS (manually). This is causing two things (warnings):

1. A Warning that metadata has changed and should be synced
2. And a Warning that the Source uses LOB-Columns and is set to Row by Row-Fetch..

Both warnings are not cool. But the second one also causes a drasticaly degredation in Performance! If I set the cast to varchar(255) the Mapping is fine (External- and Output-Column is then "Unicode string [DT_WSTR]" with a Length of 255). But as soon as I go higher, like varchar(256) it's again treated as [DT_NTEXT] in the Output.

Is there anything I can do about this? I invested days in the Evaluation of BIML and find many things an increase in Quality of Life, but this issue is killing it. It defeats the purpose of BIML if I have to correct the Errors of BIML manually after every Build.

Does anyone know how I can solve this Issue? A correct automatic Mapping between External- and Output-Columns would be great, but at least the option to define the Mapping myself would be ok.

Any Help is appreciated!

Greetings Marco

Edit As requested a Minimal Example for better understanding:

• The column in the ODBC Source (Postegres) has the type "text" (Columnname: description)
• I select it in a ODBC-Source with this Query (DirectInput): SELECT description::varchar(4000) from mySourceTable
• The ODBC-Source in Biml looks like this: SELECT description::varchar(4000) from mySourceTable
• If I now generate the dtsx-Package the ODBC-Source throws the above mentioned warnings with the above mentioned Datatypes for External and Output-Column

I am having three association tables back to back. That means item_level_1 have many item_level_2 and item_level_2 have many item_level_3. I used a search query to find any parent or child having a name containing the search text. That means if I type abc, then I need to return all parent or child with full details(parents and children). But in my case, if item_level_3 has abc in the name, it returns the parent details, but it just only returns the specific child with abc from item_level_3. I need to return all children inside item_level_3 where the same parent.

I am using MySQL database in AWS with node

I checked https://sequelize.org/master/manual/eager-loading.html#complex-where-clauses-at-the-top-level and tried different combinations. But not help. I might miss something. But I cannot find it.

I am trying to encode a small lambda calculus with algebraic datatypes in Scheme. I want it to use lazy evaluation, for which I tried to use the primitives delay and force. However, this has a large negative impact on the performance of evaluation: the execution time on a small test case goes up by a factor of 20x.

While I did not expect laziness to speed up this particular test case, I did not expect a huge slowdown either. My question is thus: What is causing this huge overhead with lazy evaluation, and how can I avoid this problem while still getting lazy evaluation? I would already be happy to get within 2x the execution time of the strict version, but faster is of course always better.

Below are the strict and lazy versions of the test case I used. The test deals with natural numbers in unary notation: it constructs a sequence of 2^24 sucs followed by a zero and then destructs the result again. The lazy version was constructed from the strict version by adding delay and force in appropriate places, and adding let-bindings to avoid forcing an argument more than once. (I also tried a version where zero and suc were strict but other functions were lazy, but this was even slower than the fully lazy version so I omitted it here.)

I compiled both programs using compile-file in Chez Scheme 9.5 and executed the resulting .so files with petite --program. Execution time (user only) for the strict version was 0.578s, while the lazy version takes 11,891s, which is almost exactly 20x slower.

I would like to convert a pandas dataframe to a multi key dictionary, using 2 ore more columns as the dictionary key, and I would like these keys to be order irrelevant.

Here's an example of converting a pandas dictionary to a regular multi-key dictionary, where order is relevant.

I've got an application where the EDM datatypes are generated during the runtime of the application (they can even change during runtime). Based loosely on OData DynamicEDMModelCreation Sample - refactored to use the new endpoint routing. There the EDM model is dynamically generated at runtime and all requests are forwarded to the same controller.

Now I wanted to update to the newest ASP.NET Core OData 8.0 and the whole routing changed so that the current workaround does not work anymore.

I've read the two blog posts of the update Blog1Blog2 and it seems that I can't use the "old" workaround anymore as the function MapODataRoute() within the endpoints is now gone. It also seems that none of the built-in routing convention work for my use-case as all require the EDM model to be present at debug time.

Maybe I can use a custom IODataControllerActionConvention. I tried to active the convention by adding it to the Routing Convention but it seems I'm still missing a piece how to activate it.

I'm trying to use the SQLProvider for MS SQL Server with F#, but it appears that it's not possible with the recommended setup.

See my module below:

In fortran you can define a default value for a variable on declaration which can be overwritten later in the code, also giving default values for all entries in an derived type array as follows:

I have a dataframe which I created from a dictionary like so: pd.DataFrame.from_dict(dict1, dtype=str)

however , the datatypes for all fields are showing up as "Object"

I want to convert some of the columns to int and/or float, but I am unable to do it even after trying several ways.

I have tried the following ways :