I see it is a pyodbc bug in the 4.0.25 version. To over-simplify, you might explain to your nervous friends that a python cursor is actually a synonym for what other languages call a recordset or resultset, and that their GUI tools are also using cursors/recordsets (but not creating a cursor on the DB!). by doing: Writing this, i understand that doing for col in colnames could be replaced by for colindex in range(0, len()) but you get the idea. Does Chain Lightning deal damage to its original target first? How to find same contact in list of contacts? In Python, how do I determine if an object is iterable? Not the answer you're looking for? Please first make sure you have looked at: To diagnose, we usually need to know the following, including version numbers. Necessary cookies are absolutely essential for the website to function properly. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Are you sure your SQL is just a SELECT The column names can be provided as the first entry of the returned list, so parsing the returned list in the calling routine can be really easy and flexible. did notice that the statement was 3222 characters long in your earlier Does Python have a ternary conditional operator? Can a rotating object accelerate by changing shape? I have been trying to understand why I was getting an error when trying to read column names from a SQL table using the cursor.columns() command. How do I use pyodbc to print the whole query result including the columns to a csv file? Im not sure that I can share the query here but I can assure you the query These cookies will be stored in your browser only with your consent. My script at The column names can be provided as the first entry of the returned list, so parsing the returned list in the calling routine can be really easy and flexible. Yes, that's the idea, although you'll probably want to get the number of records and the description from the cursor rather than the rows themselves (which I'm guessing will be rather a lot): Ran using the following code, same error as above. The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". I'm fairly certain that that trace file should cover the issue. Therefore, I would think the below outcomes are acceptable, in order of preference. to your account. Each row of returned data is represented in the returned list as a list of field (column) values. As you might be aware when you add * to a list you basically strips away the list, leaving the individual list entries as parameters to the function you are calling. By using zip we pick the 1st to n entry and zip them together like a the zipper in you pants. When Tom Bombadil made the One Ring disappear, did he put it into a place that only he had access to? substantial SQL statements. connect_string = f"DRIVER={{{self.driver}}};SERVER={self.server};PORT={self.port}; " This cookie is set by GDPR Cookie Consent plugin. How do I concatenate two lists in Python? Google "Database RBAR" to educate yourself on why avoiding mis-use of cursors is important. This article provides step-by-step guidance for installing and using the Python SQL Driver, pyODBC. Content Discovery initiative 4/13 update: Related questions using a Machine How do I connect to a MySQL Database in Python? columns For that reason, your comment is completely superfluous to me. large is iterating through several different extraction processes. How to handle Base64 and binary file content types? if cursor.description is None: are two different queries and the process fails at random. Im using bottlepy and need to return dict so it can return it as JSON. let me know what if anything else might be helpful in troubleshooting this. You mentioned earlier that the SQL is just a SELECT that returns 5 columns. I can only suggest you start By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. 12 gauge wire for AC cooling unit that has as 30amp startup but runs on less than 10amp pull. connection = pyodbc.connect(connect_string) <. What kind of tool do I need to change my bottom bracket? is a valid SQL Query. difference between cursor and connection objects. pyODBC uses the Microsoft ODBC driver for SQL Server. Try a simple SELECT ".center(100, '-')) Does contemporary usage of "neithernor" for more than two options originate in the US? I will be testing changes to sql.read_query to confirm that frame.from_records will return the resulting dataframe when columns is None. The cookie is used to store the user consent for the cookies in the category "Performance". python cursor.close(). By clicking Sign up for GitHub, you agree to our terms of service and Does contemporary usage of "neithernor" for more than two options originate in the US? dictionary What are possible reasons a sound may be continually clicking (low amplitude, no sudden changes in amplitude). The dataframe is returned without column names. is bringing back multiple result sets, so you may need to call nextset() It is unclear to me if the driver is failing to return data to pyodbc in the first place, however if there is data the data is more critical to me than the column names. Do we really need a pyodbc cursor and why? Another would be to index the column name as dictionary key with a list within each key containing the data in order of row number. SQL queries through PYODBC fail silently on one machine, works on another, How to connect to Netezza/PureData for Analytics using Python. The reason for the two different query character lengths is because they associated with them, this argument provides names for the Example assumes connection and query are built: Using @Beargle's result with bottlepy, I was able to create this very concise query exposing endpoint: Here is a short form version you might be able to use. Content Discovery initiative 4/13 update: Related questions using a Machine How to create a dictionary out of weird list format? debugging purposes. # Has to be set before creating the cursor, so we must recreate self.cursor. How to get list of dictionaries in pyodbc? columns = None The iterator, cursor.description, is sometimes empty (i.e. In this way, the routine doing the database call doesn't need to know anything about the data that it's handling. @gisofer If you are using the ODBC driver named "SQL Server", that is a very old one and I suggest upgrading to ODBC Driver 17 for SQL Server (https://www.microsoft.com/en-us/download/details.aspx?id=56567). The issue must have been rooted in an inappropriate network configuration perhaps? then it looks like the SQL statement itself is the issue here. More info about Internet Explorer and Microsoft Edge, Step 1: Configure development environment for pyodbc Python development, Step 2: Create a SQL database for pyodbc Python development, Step 3: Proof of concept connecting to SQL using pyodbc. pyODBC uses the Microsoft ODBC driver for SQL Server. Find centralized, trusted content and collaborate around the technologies you use most. Connect and share knowledge within a single location that is structured and easy to search. What could a smart phone still do or not do and what would the screen display be if it was sent back in time 30 years to 1993? , , , , . What I needed, which is slightly different than what OP was asking for: FWIW, I also added option=4 to my connection string. The issue has not appeared again since.. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Previous SQL was not a query. print(result) In order to use a cursor, we have to prove that the performance of the cursor is better than processing the rows another way. contain special characters / emojis) and the use of more unusual data types, perhaps specific to MySQL. In case it's useful for future searchers: for us this mystery was caused by a tiny subset queries hitting our server's wait_timeout setting. Will let you know what if any difference this makes. >>> single_row = dict(zip(zip(*cursor.description)[0], c pyodbc.lowercase = True self.cursor = self.cnxn.cursor() self.cursor.execute("create table t1(Abc int, dEf int)") self.cursor.execute("select * from t1") names = [ t[0] for t in query like "SELECT col1 FROM table1 LIMIT 1" using just pyodbc and see if Previous SQL was not a query." chunksize=chunksize, Microsoft contributes to the pyODBC open-source community and is an active participant in the repository at https://github.com/mkleehammer/pyodbc/. second query that I posted about is technically a few different selects http://dev.mysql.com/doc/connector-python/en/connector-python-example-cursor-select.html Their example only returns a tuple. http://www.databasejournal.com/features/mssql/article.php/3896206/What-Every-DBA-Ought-to-Know-About-SQL-Server-Cursors-and-Their-Alternatives.htm, The philosopher who believes in Web Assembly, Improving the copy in the close modal and post notices - 2023 edition, New blog post from our CEO Prashanth: Community is the future of AI. Thanks for contributing an answer to Stack Overflow! File "/usr/local/lib/python3.7/site-packages/pandas/io/sql.py", line 383, in read_sql_query How to use Django DB connection cursor in Python? In the scenario you described, I would normally expect a column count of 5. WebTeams. If you have a chance, could you check there isn't any more trace output that can be retrieved? Mainly going off @Torxed response, I created a full generalised set of functions to find the schema and data into a dictionary: Feel free to go all code-golf on this to reduce the lines; but in the meantime, it works! This cookie is set by GDPR Cookie Consent plugin. In that case, I'm afraid I'm a bit stumped. It may be difficult to try this given the inconsistent nature of the bug though. However, you may visit "Cookie Settings" to provide a controlled consent. Many thanks. The code that I am executing is as follows: How can I delete a file or folder in Python? Also getting column description using Cursor.description works fine. This AAD interactive option works if Python and pyODBC allow the ODBC driver to pop up the dialog. that works. Web PyOdbc docs # columns in table x for row in cursor.columns(table='x'): print(row.column_name) www.PyOdbc wiki API docs for row in cursor.description: print row[0] BUT' Is it possible to get more verbose logs out of the driver? How to add double quotes around string and number pattern? nature. Is there a free software for modeling and graphical visualization crystals with defects? Two faces sharing same four vertices issues. @BenLutgens Because the example produces a. Update: by default, pypyodbc sets lowercase = True. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. support Python 2.7. 2021-02-13 04:55:27,916 - INFO - Cursor initiated.. File "/usr/local/lib/python3.7/site-packages/pandas/io/sql.py", line 383, in read_sql_query Try a simple SELECT query like "SELECT col1 FROM table1 LIMIT 1" using just pyodbc and see if that works. Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Cursors Does contemporary usage of "neithernor" for more than two options originate in the US? Spellcaster Dragons Casting with legendary actions? For example, an Mainly going off @Torxed response, I created a full generalised set of functions to find the schema and data into a dictionary: Feel free to go all code-golf on this to reduce the lines; but in the meantime, it works! Asking for help, clarification, or responding to other answers. Note, pyodbc contains C++ extensions so you will Making statements based on opinion; back them up with references or personal experience. Zero output columns would explain the empty query description you got. rev2023.4.17.43393. I have written a nice little generalised schema gatherer: @FooStack Column names are already returned in, Output pyodbc cursor results as python dictionary, The philosopher who believes in Web Assembly, Improving the copy in the close modal and post notices - 2023 edition, New blog post from our CEO Prashanth: Community is the future of AI. Thanks for contributing an answer to Stack Overflow! To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Q&A for work. Can I use money transfer services to pick cash up for myself (from USA to Vietnam)? Nevertheless, I will attempt to recreate the issue with trace logs and send another trace file. But I found this way neat, as its also injection safe. How to determine chain length on a Brompton? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. On the other hand this option works and gives the column names: columns = [column[0] for column in cursor.description] If the error returned is still "No results. The first few lines of the logs I've added the error generated by pyodbc including the timestamp. Makes sense, that I have to use the csv module. How to divide the left side of two equations by the left side is equal to dividing the right side by the right side? I use python every day with a heavy emphasis on database work. Previous SQL was not a query. SELECT statement (however complex it might be). rev2023.4.17.43393. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. Why don't objects get brighter when I reflect their light back at them? Sci-fi episode where children were actually adults, Review invitation of an article that overly cites me and the journal. the SQL, please do, otherwise please check it to make sure it is a single Web pandas MS SQL Server, pyodbc. The first query has the majority of those unions commented out for When Tom Bombadil made the One Ring disappear, did he put it into a place that only he had access to? Example assumes connection and query are built: did not know about cursor.description. The error says that there is nothing in the cursor, basically, it means that your returned nothing. Can we create two different filesystems on a single partition? 5 How to create a dictcursor in Python MySQL? I am reviewing a very bad paper - do I have to be nice? If your version of the ODBC driver is 1 If a people can travel space via artificial wormholes, would that necessitate the existence of time travel? result = cur.fetchall() columns. Also I did not mention this before but I am running this in a container in aws but I have also produced this error locally. On Sat, Feb 13, 2021 at 08:16 Keith Erskine ***@***. for col in cursor.columns(table='SOURCE'): print(col.column_name) As you might be aware when you add * to a list you basically strips away the list, leaving the individual list entries as parameters to the function you are calling. The table itself can be accessed: if cursor.tables(table='SOURCE').fetchone(): print('yes it does') Not the answer you're looking for? Can someone please tell me what is written on this score? Note: This error was produced using MySQL ODBC 8.0.22 Unicode Driver making it the second driver that I've produced this error on. That's an indexed version, not the most beautiful solution but it will work. can one turn left and right at a red light with dual lane turns? I noticed this diagnosis error: "MySQL server has gone away" however it seems this follows the error from pyodbc. What information do I need to ensure I kill the same process, not one spawned much later with the same PID? PyODBC is community-supported software. I overpaid the IRS. Got the same problem for Microsoft Access Driver (*.mdb) - (older) 32-bit "Jet" ODBC driver: mentioned earlier that the SQL is just a SELECT that returns 5 columns. Making statements based on opinion; back them up with references or personal experience. Database cursors map to ODBC handles statements (HSTMTs). Is it possible to create a dictionary cursor using this MySQL connector? This is also seen in the logs you mentioned and in the error I'm getting now. How to determine chain length on a Brompton? I Here is a short form version you might be able to use >>> cursor.select("") Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features. Connect and share knowledge within a single location that is structured and easy to search. Asking for help, clarification, or responding to other answers. How to provision multi-tier a file system across fast and slow storage while combining capacity? no data for query columns is available) and the query will fail with the aforementioned error. privacy statement. Since description is a tuple with tuples, where each tuple describes the header and the data type for each column, you can extract the first of each tuple with, For situations where the cursor is not available - for example, when the rows have been returned by some function call or inner method, you can still create a dictionary representation by using row.cursor_description. The proposed workaround is not reliable, cause cursor.columns(table=table_name) is not complete: Using @Beargle's result with bottlepy, I was able to create this very concise query exposing endpoint: @route('/api/query/') Evaluating the limit of two sums/sequences. I am still on pyodbc 4.0.30, my query has not changed, and my MySql version has not changed. What screws can be used with Aluminum windows? Ive been working with SQL for a few years now. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. http://www.databasejournal.com/features/mssql/article.php/3896206/What-Every-DBA-Ought-to-Know-About-SQL-Server-Cursors-and-Their-Alternatives.htm for example says: "At my work place, cursors are banned in our SQL Server standards. You get, e.g. How to get list of dictionaries from cursor? Sign up for a free GitHub account to open an issue and contact its maintainers and the community. The pyodbc 5.x versions will only support Python 3.7 and above. So now you can execute your sql query and you'll get a dictionary to fetch your results, without the need to map them by hand. On Sat, Feb 13, 2021 at 19:39 Keith Erskine ***@***. I have the same problem as @gisofer How do I serialize pyodbc cursor output (from .fetchone, .fetchmany or .fetchall) as a Python dictionary? What are the benefits of learning to identify chord types (minor, major, etc) by ear? 9. For documentation, see pyodbc documentation. pyodbc.cursor.columns doesn't always return table column information, https://github.com/mkleehammer/pyodbc/wiki, cursor.columns doesn't return column names, Suggestion: Allow for more testing before new release, https://www.microsoft.com/en-us/download/details.aspx?id=56567, pyodbc cursor.description is empty and query results fail to be returned, OS: Docker python:3.7 i.e. rev2023.4.17.43393. Connect and share knowledge within a single location that is structured and easy to search. Content Discovery initiative 4/13 update: Related questions using a Machine Get the column names of a query from pyodbc? pyodbc: 4.0.38 OS: Windows 10 Enterprise 20H2 64-bit DB: Impala driver: Cloudera ODBC Driver for Impala 2.06.16.1022 import pyodbc conn = connect 'DSN=Hadoop LDAP', autocommit=True cur = conn. cursor cur. pypyodbc, Python: pandas.DatetimeIndex frequency is None and can't be set, Python: Get Public URL for File - Google Cloud Storage - App Engine (Python), Performance: Concatenate many nd-arrays of different shapes (filling values until the edges), How can I setup a python CLI application so that I can use it without directly referring to the interpreter in Python, Django + PostgreSQL best way to improve performance of slow summary aggregation in Sql. I overpaid the IRS. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. How can I access environment variables in Python? driver: SQL Server. How does claims based authentication work in mvc4? Why is Noether's theorem not guaranteed by calculus? almost certainly not a SELECT statement but something else. 1 When to use cursor description in pyodbc? By clicking Accept All, you consent to the use of ALL the cookies. operating systems this will build from source. These cookies ensure basic functionalities and security features of the website, anonymously. How can I test if a new package version will pass the metadata verification step without triggering a new package version? If you are working with postgresql and you are using psycopg2 you could use some goodies from psycopg2 to achieve the same by specifying the cursorfactory being a DictCursor when creating your cursor from the connection, like this: cur = conn.cursor( cursor_factory=psycopg2.extras.DictCursor ). Remark: You can dump all results to the csv file without looping: Wouldn't that fit the entire result set in memory, @MilovanTomaevi? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. 4 How to use Django DB connection cursor in Python? Is there a way to use any communication without a CPU? To get help, file an issue in the pyODBC GitHub repository or visit other Python community resources. Please note that you'll have to import psycopg2.extras for that to work. line 132, in query_sql Please Older version however, It Reference: is this exposed to SQL injection attacks? and if i need want to reuse the cursor for another query instead of creating a new cursor, I can store the result set from the first query like so: This approach has worked well for me so far. Python cursor3 : psycopg2SQLCURSOR(FETCH, Not the answer you're looking for? In this way, the routine doing the database call doesn't need to know anything about the data that it's handling. pandas.pydata.org/pandas-docs/stable/generated/, The philosopher who believes in Web Assembly, Improving the copy in the close modal and post notices - 2023 edition, New blog post from our CEO Prashanth: Community is the future of AI. Good luck. Please note that you'll have to import psycopg2.extras for that to work. the docs for details. You also have the option to opt-out of these cookies. Since description is a tuple with tuples, where each tuple describes the header and the data type for each column, you can extract the first of each tuple with. Evaluating the limit of two sums/sequences. File "/usr/local/lib/python3.7/site-packages/pandas/io/sql.py", line 1766, in read_query What does Canada immigration officer mean by "I'm not satisfied that you will leave Canada based on your purpose of visit"? But that is complete conjecture. (NOT interested in AI answers, please). It does not store any personal data. Unfortunately, I do not have much of an update. See If you're OK posting the SQL, please do, otherwise please check it to make sure it is a single SELECT statement (however complex it might be). The easiest way to install is to use pip: If you are using Mac, you should be using Homebrew for installing pyodbc: Precompiled binary wheels are provided for most Python versions on Windows and macOS. How to add double quotes around string and number pattern? DB: Microsoft SQL Server Standard (64-bit), Version 12.0.6024.0 Openbase helps you choose packages with reviews, metrics & categories. Making statements based on opinion; back them up with references or personal experience. print the same SQL scripts and can confirm that at final stage prior to I use python every day with a heavy emphasis on database work. Alternative ways to code something like a table within a table? The problem is that with Cursor.columns sometimes I get data and sometimes not. I imagine the creators of MySQL would eventually do this for us? Lastly, there's always the remote possibility your query Openbase is the leading platform for developers to discover and choose open-source. Debian 9 (Docker running on MacOS Mojave), DB: Netsuite (some Oracle SQL database flavour), driver: Netsuite ODBC driver Linux64bit 7.2.0.0050. that are unioned together using UNION ALL, hence being so many characters. Thank you @keitherskine, Hi @keitherskine I was finally able to reproduce the issue. If you don't know columns ahead of time, use Cursor.description to build a list of column names and zip with each row to produce a list of dictionaries. pyodbc Can someone explain the difference between these ODBC cursors and SQL Server type cursors (assuming I'm correct that they are different)? Connect and share knowledge within a single location that is structured and easy to search. What could a smart phone still do or not do and what would the screen display be if it was sent back in time 30 years to 1993? How to select database in django db collection custom query? ***> wrote: If the passed data do not have names Step 2: Create a SQL database for pyodbc Python development. crsr.columns(table='') should return always the column description for the given table, "observed behavior". Lastly, there's always the remote possibility your query is bringing back multiple result sets, so you may need to call nextset() to get the result set (and description) you're looking for. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. connection_hostname same queries execute fine using my script more than half the time and can Example Yeah Ive thought about trying the same.. Ill give it a shot, thanks! The server is a client server and therefore I am unable to upgrade MySql version, however the issue occurs both on MySql 8 and MySql 5.6. For example, an UPDATE statement, or a statement that is not a data query (e.g. I kind of see the need of a cursor when fetching rows. The trace ends just as the SQL query is executed (the SQL that starts with "WITH NewEncounters AS"). You signed in with another tab or window. If master doesn't fix it, please reopen this, but I'm pretty sure it will. also execute successfully when using DBeaver. You are receiving this because you modified the open/close state. If the error returned is still "No results. Already on GitHub? When data is available is fully correct. Sign in deleting specific dictionary items in python (based on key format) in Python. Asking for help, clarification, or responding to other answers. Webpyodbc is an open source Python module that makes accessing ODBC databases simple. ODBCTrace.txt. That seems odd.