I want to load my Microsoft.Data.Analysis Dataframe into a SQL Server table. I somehow learnt that I should use Entity Framework for that, but I haven't found a solution similar to Pythons Sqlalchemy pandas.dataframe.tosql() method. Is there an easy way to achieve that?
I've already tried Googling that of course, but sadly that did not lead to any results, is it possible at all?
Thanks in advance for any help and have a lovely day
Right now, no. The Microsoft.Data.Analysis namespace is somewhat ... aspirational and can't even be used to load data from a database. It's an attempt to create something like Pandas Dataframes in the future and has nothing at all to do with Entity Framework.
If you want a DataFrame-like type in .NET, check the Deedle library which is used in F# data analysis programming.
Another option is to keep using Python, or learn Python, Pandas and Notebooks. Even Visual Studio Code and Azure Data Studio offer better support for Pandas and Notebooks than Microsoft.Data.Analysis.
The problem is that until recently Microsoft put all its effort in ML, not analysis. And Microsoft.Data.Analysis is part of the ML repository, so it got little attention since its introduction 2 years ago.
This changed on March 2022, when the DataFrame (Microsoft.Data.Analysis) Tracking Issue was created to track and prioritize what programmers wanted from a .NET Dataframe type. Loading from a database is open for 2 years without progress.
Loading from SQL
If you want to use Microsoft.Data.Analysis.DataFrame right now you'll have to write code similar to the CSV loading code:
Create a list of DataFrameColumns from a DataReader's schema. This can be retrieved with DbDataReader.GetSchemaTable.
Create a DataFrame with those columns
For each row, append the list of values to the dataframe. The values could be retrieved with DbDataReader.GetValues
Loading from Excel
The same technique can be used if the Excel file is loaded using a library like ExcelDataReader that exposed the data through a DataReader. The library doesn't implement all methods though, so some tweaking may be needed if eg GetValues doesn't work.
Writing to SQL
That's harder because you can't just send a stream of rows to a table. A DataFrame is a collection of Series too, not rows. You'd have to construct the INSERT SQL command from the column names, then execute it with data from each row.
A dirty way would be to convert the DataFrame into a DataTable and save that using a DataAdapter. That would create yet another copy of the data in memory though.
A better way would be to create a DataReader wrapper over a DataFrame, and pass that reader to eg SqlBulkCopy
Related
So my team is looking into connecting to Netezza with C# and we plan on loading data into netezza, pulling data from netezza and writing update queries all in C#.
From my research, I see that it's possible to connect to netezza using C# and I'm wondering if you can do all that is bolded above using C# so that we can decide on whether or not we can do just about anything with Netezza using C#. We'd like to know before we commit to anything. The types of data we would be loading are CSV files.
Are there any good resources on this? I haven't been able to find any.
We also have Aginity client tools so maybe it's possible to incorporate Aginity to this (Not that I would want to but if it's easier I'd like to know about it)?
Retrieving data is straightforward and can be done through the usual channels (loop over a cursor to get results) but loading can take a bit longer.
Netezza is not a fan of multiple INSERT queries; loading a large number of records with individual INSERT queries, as it doesn't support multi-row inserts, will take a long time.
When loading multiple records most people usually write out their data to a ".csv" and use the external table syntax to perform the insert.
When in a application we prefer to load/unload our data via a named pipe so that we don't have to write/read the data to disk prior.
I want to read some data from a .csv file and store them in a DB2 table using C#. I am new to both C# and DB2.
I just have two values separated by commas in each line of the .csv file.
Could someone provide me some link or sample code for my purpose?
I can insert into a DB2 table using hard-coded values. But I am not able to insert in a loop using variables.
Any kind of help would be appreciated.
Thanks in advance.
For your first problem, reading from a .csv file, here's a link that shows how to read from a .CSV file. This example will store what it reads from your .csv file into a collection (a string array) called Fields. You could easily store it in a data table. That way, you can step through each row of the data table and write it out to your DB2 database.
Now, the second part of your problem, writing to a DB2 table, depends on what technology you'd like to use. LINQ, Entity Framework, T-SQL, etc. You need to read up on these to figure out how to take your collection of data and write it out to a DB2 database. There are tons of tutorials online and quite a few good ones on YouTube.
What you're attempting to do is easy enough, but only with understanding each part of the problem, with regards to how to leverage C# to solve the problem. Please try to go one step-at-a-time. Learning C# can be daunting if you try to rush it. Take your problem, make a list of each step that you want to accomplish, and go from there.
I have a code related to dbf operation in Visual foxpro as given below .
SELECT 3
USE student shared
SET FILTER TO
LOCATE FOR id=thisform.txtStudentID.Value
can any one help me to understand the each line of code and convert to C#.net.What are the steps to be taken to convert foxpro code to C# ? Here I am using SQL Server as backend in C# Project.Some times I have faced the below type of code also
Use Student Shared
// Here accessing the database fields directly.Here Are they targeting to get all records like "select * from student" or only last record.By default this student table has 6 columns but in the dbf file we have 12 columns. How can do this in C#.NET?
To answer part of your question - what does this code do...
The following sets a work area (I haven't done foxpro for a few years now, but think this is redundant in the later versions of VFP). A work area is just a space in memory which is kept sperate from other work spaces.
Select 3
The following opens a table called 'Student' for non-readonly access into the previously opened workspace
USE student shared
The following clears all filters on the table (so if you 'BROWSE' you will get all records)
SET FILTER TO
The following will set the record pointer to a specific record where the record with an id is equal to the txtStudentID textbox value on the current form (foxpro is not a strongly typed language)
LOCATE FOR id=thisform.txtStudentID.Value
For the second part of your question, there is no direct way to convert between foxpro and a c# application. The main points are that Foxpro is built around a database and is not strongly typed whereas c# is stongly typed and can access a database. If you do a quick google search you will probably find tools written by people like Markus Egger to convert from foxpro to c#.
IMHO and from experience of migrating an enterprise sized system from VFP to c# / SQL server - if you want to do this with a system - stop, convince yourself it is a bad idea and just re-write the thing in c# - picking a database that best suits your needs.
It's hard to comment further - you haven't stated what version of foxpro you are using - are you using foxpro or visual foxpro? What size is your application, what is the background?
HTH
Jay
There is no way to directly convert that to C#.
SELECT 3
FoxPro has the concept of 'work areas' - like slots, each of which can have an opened DBF file in it. This command says "OK - we're looking at work area 3."
This has no equivalent in .NET
USE student SHARED
This will open student.dbf, in the current directory, for shared access in work area 3.
SET FILTER TO
If we have a filter set, which will limit what records are available, clear that filter now. Pointless, as we've just opened the table and we didn't set a filter.
LOCATE FOR id=thisform.txtStudentID.Value
Find the first record where id = thisform.txtStudentID.Value. The latter part is a custom property of the form that is running this code.
So all this code is doing is locating a record in student.dbf based on a value. If you wanted to pull that record back in C# using the OLE DB provider you could check How to load DBF data into a DataTable.
The SET FILTER TO is not needed as the table is being used (opened) so there is no filter to clear. To convert this bit of FoxPro to C#:
SELECT * FROM student WHERE id=thisform.txtStudentID.Value
You would then have to loop the results (if any). Best practices would be to use a parameter for the WHERE clause value to prevent SQL injection.
I find myself in possession of an Excel Spreadsheet containing about 3,000 rows of data that represent either additions or changes to data that I need to make to an SQL Table. As you can imagine that's a bit too much to handle manually. For a number of reasons beyond my control, I can't simply use an SSIS package or other simpler method to get these changes into the database. The only option I have is to create SQL scripts that will make the changes represented in the spreadsheet to MS SQL 2005.
I have absolutely no experience with Office automation or VSTO. I've tried looking online, but most of the tutorials I've seen seem a bit confusing to me.
So, my thought is that I'd use .NET and VSTO to iterate through the rows of data (or use LINQ, whatever makes sense) and determine if the item involved is an insert or an update item. There is color highlighting in the sheet to show the delta, so I suppose I could use that or I could look up some key data to establish if the entry exists. Once I establish what I'm dealing with, I could call methods that generate a SQL statement that will either insert or update the data. Inserts would be extremely easy, and I could use the delta highlights to determine which fields need to be updated for the update items.
I would be fine with either outputting the SQL to a file, or even adding the test of the SQL for a given row in the final cell of that row.
Any direction to some sample code, examples, how-tos or whatever would lead me in the right direction would be most appreciated. I'm not picky. If there's some tool I'm unaware of or a way to use an existing tool that I haven't thought of to accomplish the basic mission of generating SQL to accomplish the task, then I'm all for it.
If you need any other information feel free to ask.
Cheers,
Steve
I suggest before trying VSTO, keep things simple and get some experience how to solve such a problem with Excel VBA. IMHO that is the easiest way of learning the Excel object model, especially because you have the macro recorder at hand. You can re-use this knowledge later when you think you have to switch to C#, VSTO or Automation or (better !) Excel DNA.
For Excel VBA, there are lots of tutorials out there, here is one:
http://www.excel-vba.com/excel-vba-contents.htm
If you need to know how to execute arbitrary SQL commands like INSERT or UPDATE within a VBA program, look into this SO post:
Excel VBA to SQL Server without SSIS
Here is another SO post showing how to get data from an SQL server into an Excel spreadsheet:
Accessing SQL Database in Excel-VBA
I need to import the data form .csv file into the database table (MS SQL Server 2005). SQL BULK INSERT seems like a good option, but the problem is that my DB server is not on the same box as my WEB server. This question describes the same issue, however i don't have any control over my DB server, and can't share any folders on it.
I need a way to import my .csv programatically (C#), any ideas?
EDIT: this is a part of a website, where user can populate the table with .csv contents, and this would happen on a weekly basis, if not more often
You have several options:
SSIS
DTS
custom application
Any of these approaches ought to get the job done. If it is just scratch work it might be best to write a throwaway app in your favorite language just to get the data in. If it needs to be a longer-living solution you may want to look into SSIS or DTS as they are made for this type of situation.
Try Rhino-ETL, its an open source ETL engine written in C# that can even use BOO for simple ETL scripts so you don't need to compile it all the time.
The code can be found here:
https://github.com/hibernating-rhinos/rhino-etl
The guy who wrote it:
http://www.ayende.com/blog
The group lists have some discussions about it, I actually added bulk insert for boo scripts a while ago.
http://groups.google.com/group/rhino-tools-dev
http://groups.google.com/group/rhino-tools-dev/browse_thread/thread/2ecc765c1872df19/d640cd259ed493f1
If you download the code there are several samples, also check the google groups list if you need more help.
i ended up using CSV Reader. I saw a reference to it in one of the #Jon Skeet's answers, can't find it again to put the link to it
How big are your datasets? Unless they are very large you can get away with parameterized insert statements. You may want to load to a staging table first for peace of mind or performance reasons.