# Data

**URL:** https://discourse.julialang.org/c/domain/data/16.md

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

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## [About the Data category](https://discourse.julialang.org/t/about-the-data-category/129)

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**Author:** [@vchuravy](https://discourse.julialang.org/u/vchuravy)\
**Replies:** 0

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This subcategory is for discussion around data management: importing/exporting data sets from files or databases, manipulating data, summarizing data, etc. Also welcomed is discussion about the projects or packages main…

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## [Using FunSQL.jl with Postgres.jl](https://discourse.julialang.org/t/using-funsql-jl-with-postgres-jl/139564)

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**Author:** [@Jake](https://discourse.julialang.org/u/Jake)\
**Replies:** 1\
**Last updated:** [September 24, 2026, 4:45pm UTC](https://discourse.julialang.org/t/using-funsql-jl-with-postgres-jl/139564 "2026-09-24T16:45:07Z")

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I am testing Postgres.jl with my package that currently uses LibPQ and FunSQL. The testing so far which did not include FunSQL worked well. I am getting stuck on the FunSQL integration. LibPQ.jl does not support the D…

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## [Write CSV row by row](https://discourse.julialang.org/t/write-csv-row-by-row/138171)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 8\
**Last updated:** [September 17, 2026, 6:15pm UTC](https://discourse.julialang.org/t/write-csv-row-by-row/138171 "2026-09-17T18:15:14Z")

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I have a computation that calculates rows of data, let’s say they are NamedTuples with the same keys. I would like to emit this into a CSV file without collecting or making it an iterable. ▶ Why? Pseudocode for what I wa…

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## [Parsequoted=true in JSON.jl](https://discourse.julialang.org/t/parsequoted-true-in-json-jl/139486)

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**Author:** [@freeman](https://discourse.julialang.org/u/freeman)\
**Replies:** 4\
**Last updated:** [September 17, 2026, 2:22pm UTC](https://discourse.julialang.org/t/parsequoted-true-in-json-jl/139486 "2026-09-17T14:22:13Z")

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JSON3 had the ability to automatically handle quoted numbers. For example import JSON3 struct MyType x::Float64 end s = "{\\"x\\":\\"4.0\\"}" # note quoted "4.0" JSON3.read(s, MyType; parsequoted=true) # MyType(4.0…

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## [Package technical spec feedback](https://discourse.julialang.org/t/package-technical-spec-feedback/139056)

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**Author:** [@mthelm85](https://discourse.julialang.org/u/mthelm85)\
**Replies:** 1\
**Last updated:** [September 16, 2026, 2:18pm UTC](https://discourse.julialang.org/t/package-technical-spec-feedback/139056 "2026-09-16T14:18:48Z")

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About 6 months ago, I threw together a quick & dirty (unregistered) package that I called DataMimic for generating synthetic data, based on a real dataset. It was okay for what I needed it for at the time, but it’s defin…

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## [Deprecating EzXML.jl?](https://discourse.julialang.org/t/deprecating-ezxml-jl/137622)

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**Author:** [@nhz2](https://discourse.julialang.org/u/nhz2)\
**Replies:** 3\
**Last updated:** [September 15, 2026, 8:57am UTC](https://discourse.julialang.org/t/deprecating-ezxml-jl/137622 "2026-09-15T08:57:49Z")

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EzXML.jl has a number of serious bugs. For example: Segfault when using \`link!\` · Issue #218 · JuliaIO/EzXML.jl · GitHub Is anyone currently maintaining this package? Should we mark this package as deprecated in the re…

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## [HDF5.jl with vector of tuples of strings](https://discourse.julialang.org/t/hdf5-jl-with-vector-of-tuples-of-strings/139148)

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**Author:** [@BambOoxX](https://discourse.julialang.org/u/BambOoxX)\
**Replies:** 4\
**Last updated:** [September 2, 2026, 7:25am UTC](https://discourse.julialang.org/t/hdf5-jl-with-vector-of-tuples-of-strings/139148 "2026-09-02T07:25:32Z")

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@mkitti I just stumbled on another similar string related issue. If one tries to write a Vector{@NamedTuple...} where at least one type is a string, the writing fails. This is on v0.17.3. using HDF5 arr = \[ (;A…

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## [How do you get formulas created by XLSX.jl to be read automatically in Excel?](https://discourse.julialang.org/t/how-do-you-get-formulas-created-by-xlsx-jl-to-be-read-automatically-in-excel/75701)

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**Author:** [@scotts](https://discourse.julialang.org/u/scotts)\
**Replies:** 3\
**Last updated:** [August 29, 2026, 5:46pm UTC](https://discourse.julialang.org/t/how-do-you-get-formulas-created-by-xlsx-jl-to-be-read-automatically-in-excel/75701 "2026-08-29T17:46:34Z")

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I’m making Excel files with XLSX.jl. Everything works as it should, however, I’ve found when I create formulas for the spreadsheet they just show up as text in Excel. I can manually get them to register and process if …

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## [Generate excel spreadsheet from julia equations?](https://discourse.julialang.org/t/generate-excel-spreadsheet-from-julia-equations/92444)

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**Author:** [@OliverEvans96](https://discourse.julialang.org/u/OliverEvans96)\
**Replies:** 1\
**Last updated:** [August 29, 2026, 5:43pm UTC](https://discourse.julialang.org/t/generate-excel-spreadsheet-from-julia-equations/92444 "2026-08-29T17:43:11Z")

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Hi all, Imagine a spreadsheet with columns A, B, C. Suppose A are observations, and B = B(A), C = C(A, B) are defined by excel formulas involving the previous columns. This is a pretty common scenario in excel. I was j…

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## [Reading STDF Tester Data Files](https://discourse.julialang.org/t/reading-stdf-tester-data-files/14216)

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**Author:** [@Ed\_Ferrari](https://discourse.julialang.org/u/Ed_Ferrari)\
**Replies:** 1\
**Last updated:** [May 17, 2026, 8:19pm UTC](https://discourse.julialang.org/t/reading-stdf-tester-data-files/14216 "2026-05-17T20:19:56Z")

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Totally new to Julia but considering learning it to develop analysis tools for our test data. Our most common format for tester data is STDF Teradyne Test Data Format. Is there a way to import STDF file fomated data for …

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## [Should ownership of XLSX.jl transfer to JuliaData?](https://discourse.julialang.org/t/should-ownership-of-xlsx-jl-transfer-to-juliadata/135023)

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**Author:** [@TimG](https://discourse.julialang.org/u/TimG)\
**Replies:** 13\
**Last updated:** [March 13, 2026, 12:29am UTC](https://discourse.julialang.org/t/should-ownership-of-xlsx-jl-transfer-to-juliadata/135023 "2026-03-13T00:29:13Z")

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XLSX.jl seems to be a well used package. It has 298 stars on GitHub, for example. Unfortunately, the package owner seems no longer to be active, and so active maintenance of the package has more or less stopped. Excel i…

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## [Why does transform default to ungroup=true?](https://discourse.julialang.org/t/why-does-transform-default-to-ungroup-true/92544)

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**Author:** [@jar1](https://discourse.julialang.org/u/jar1)\
**Replies:** 2\
**Last updated:** [March 2, 2026, 10:54am UTC](https://discourse.julialang.org/t/why-does-transform-default-to-ungroup-true/92544 "2026-03-02T10:54:07Z")

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In DataFrames, why does transform default to ungroup=true?

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## [SDMX parser](https://discourse.julialang.org/t/sdmx-parser/61143)

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**Author:** [@gr\_julia](https://discourse.julialang.org/u/gr_julia)\
**Replies:** 2\
**Last updated:** [February 12, 2026, 2:59am UTC](https://discourse.julialang.org/t/sdmx-parser/61143 "2026-02-12T02:59:02Z")

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Hi all, I’m new to Julia and trying to automate data retrieval. That’s fairly easy for JSON formats but many organisations now use SDMX-ML. I could not find a parser though (and have no idea how to write one). Has anyon…

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## [Pre-computing Groupings for DataFrames?](https://discourse.julialang.org/t/pre-computing-groupings-for-dataframes/134973)

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**Author:** [@nateybear](https://discourse.julialang.org/u/nateybear)\
**Replies:** 6\
**Last updated:** [January 10, 2026, 9:12pm UTC](https://discourse.julialang.org/t/pre-computing-groupings-for-dataframes/134973 "2026-01-10T21:12:05Z")

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Hi! I’m writing to check my understanding of a computational problem and see if I am approaching things correctly. I am writing estimation code that needs to traverse data in multiple different ways. The typical approac…

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## [Decompression of large files](https://discourse.julialang.org/t/decompression-of-large-files/132191)

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**Author:** [@mdotend](https://discourse.julialang.org/u/mdotend)\
**Replies:** 11\
**Last updated:** [November 8, 2025, 6:40pm UTC](https://discourse.julialang.org/t/decompression-of-large-files/132191 "2025-11-08T18:40:51Z")

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Hey there, I am currently trying to work with dumps of reddit data which is alot of compressed json data in the zst format (e.g. 11GB for one month of submissions). When I try to read lines from that data I get an unspe…

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## [Side effects (or intended effects) in TidierData?](https://discourse.julialang.org/t/side-effects-or-intended-effects-in-tidierdata/133438)

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**Author:** [@rocco\_sprmnt21](https://discourse.julialang.org/u/rocco_sprmnt21)\
**Replies:** 11\
**Last updated:** [October 31, 2025, 10:53pm UTC](https://discourse.julialang.org/t/side-effects-or-intended-effects-in-tidierdata/133438 "2025-10-31T22:53:35Z")

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julia\> df4 = DataFrame(x = \["a", "b", "a", "b", "C", "a"\], y = 1:6, yz = 13:18, a = \[join(rand('a':'z',4)) for \_ in 1:6\], ab = 12:-1:7) 6×5 DataFrame Row │ x y yz a ab │ String Int64 Int6…

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## [CSV.jl "corrupts" data when a field is very large](https://discourse.julialang.org/t/csv-jl-corrupts-data-when-a-field-is-very-large/133513)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 6\
**Last updated:** [October 30, 2025, 1:06pm UTC](https://discourse.julialang.org/t/csv-jl-corrupts-data-when-a-field-is-very-large/133513 "2025-10-30T13:06:08Z")

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I have a CSV (from here) where one field is a MULTIPOLYGON that can be very large, and when I import it with CSV (even a smaller 10 rows version) I got a strange corruption: julia\> data = CSV.read("MYRIAD-HES/test.cs…

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## [Package for general purpose neuroimaging](https://discourse.julialang.org/t/package-for-general-purpose-neuroimaging/58147)

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**Author:** [@shak360](https://discourse.julialang.org/u/shak360)\
**Replies:** 5\
**Last updated:** [October 7, 2025, 8:14am UTC](https://discourse.julialang.org/t/package-for-general-purpose-neuroimaging/58147 "2025-10-07T08:14:09Z")

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Is there a package for general purpose neuroimaging? Specifically, does something akin to nibabel in Python for handling DICOM or NIFTI images exist?

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## [Dataframe viewer needed](https://discourse.julialang.org/t/dataframe-viewer-needed/9239)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 28\
**Last updated:** [September 23, 2025, 12:36pm UTC](https://discourse.julialang.org/t/dataframe-viewer-needed/9239 "2025-09-23T12:36:25Z")

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I think a dataframe viewer where I can look at each row and column and if needed can scroll across up and down are needed. I know atom has a CSV editor plugin. Perhaps can repurpose that. I know it’s a lot of work but i…

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## [Packages for representing time series data](https://discourse.julialang.org/t/packages-for-representing-time-series-data/84699)

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**Author:** [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)\
**Replies:** 14\
**Last updated:** [September 23, 2025, 12:55pm UTC](https://discourse.julialang.org/t/packages-for-representing-time-series-data/84699 "2025-09-23T12:55:50Z")

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DataFrames.jl seems to be the go to package for representing tabular data. It is very performant and well maintained. However, if someone has strictly structured data like time series data (i.e. a vector of timestamp an…

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## [Cannot fix \`nothing\` in summation](https://discourse.julialang.org/t/cannot-fix-nothing-in-summation/132507)

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**Author:** [@rgouveiamendes](https://discourse.julialang.org/u/rgouveiamendes)\
**Replies:** 7\
**Last updated:** [September 19, 2025, 2:04pm UTC](https://discourse.julialang.org/t/cannot-fix-nothing-in-summation/132507 "2025-09-19T14:04:40Z")

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Hello, I am trying to perform the following transformation on a DataFrame: @transform! df\_20\_P\_raw\[:data\] begin # Calculate the sum of the relevant columns, replacing missing values with 0 :pensions\_balance\_pro…

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## [ODBC.jl to connect to an Oracle database on Linux](https://discourse.julialang.org/t/odbc-jl-to-connect-to-an-oracle-database-on-linux/97037)

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**Author:** [@klwlevy](https://discourse.julialang.org/u/klwlevy)\
**Replies:** 5\
**Last updated:** [September 15, 2025, 5:39am UTC](https://discourse.julialang.org/t/odbc-jl-to-connect-to-an-oracle-database-on-linux/97037 "2025-09-15T05:39:08Z")

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Hi there, I am succesfully using ODBC.jl to connect to an Oracle database on my local Windows laptop (with system-provided DSN from Windows ODBC). Now I am struggling to connect to the same database from a server runnin…

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## [Deconstruct NamedTupleColumn with Prefix](https://discourse.julialang.org/t/deconstruct-namedtuplecolumn-with-prefix/131297)

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**Author:** [@mreichMPI-BGC](https://discourse.julialang.org/u/mreichMPI-BGC)\
**Replies:** 5\
**Last updated:** [August 5, 2025, 9:17pm UTC](https://discourse.julialang.org/t/deconstruct-namedtuplecolumn-with-prefix/131297 "2025-08-05T21:17:23Z")

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Similar to this one: Transform! to destructure NamedTuple into columns I’d like to do the same, but be able to programmatically prefix the "child"columns with the “parent” prefix. That is in the linked MWE, I would lik…

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## [Pretty print summary statistics for a dataframe](https://discourse.julialang.org/t/pretty-print-summary-statistics-for-a-dataframe/129838)

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**Author:** [@theabhirath](https://discourse.julialang.org/u/theabhirath)\
**Replies:** 4\
**Last updated:** [June 15, 2025, 2:27am UTC](https://discourse.julialang.org/t/pretty-print-summary-statistics-for-a-dataframe/129838 "2025-06-15T02:27:29Z")

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I’m looking to print out a summary of missing values in each row and column for a dataframe, but ideally I want to print it alongside the actual dataframe itself – in my head it looks something like this (pardon the crud…

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## [Indexing by names, current favorites in the package space](https://discourse.julialang.org/t/indexing-by-names-current-favorites-in-the-package-space/123097)

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**Author:** [@cdawg](https://discourse.julialang.org/u/cdawg)\
**Replies:** 7\
**Last updated:** [June 6, 2025, 8:40pm UTC](https://discourse.julialang.org/t/indexing-by-names-current-favorites-in-the-package-space/123097 "2025-06-06T20:40:18Z")

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I loved AxisArrays.jl. However AxisArrays is old (designed pre1.0). It still works…ok, but I miss broadcasting and Not-.indexing. I did not learn about its newer counterparts until I had written a few weeks of analysis a…

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## [DuckDB Array Not Supported?](https://discourse.julialang.org/t/duckdb-array-not-supported/129508)

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**Author:** [@NAS](https://discourse.julialang.org/u/NAS)\
**Replies:** 3\
**Last updated:** [June 1, 2025, 5:28am UTC](https://discourse.julialang.org/t/duckdb-array-not-supported/129508 "2025-06-01T05:28:01Z")

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I was able to use the DuckDB Appender API to insert data into a table in the form of: CREATE OR REPLACE TABLE embeds (id INTEGER PRIMARY KEY, acc STRING, esm\_embed NUMERIC(9,8)\[1280\]) where the esm\_embed column is a ve…

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## [Using DuckDB appender with JSON column](https://discourse.julialang.org/t/using-duckdb-appender-with-json-column/129283)

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**Author:** [@slwu89](https://discourse.julialang.org/u/slwu89)\
**Replies:** 5\
**Last updated:** [May 31, 2025, 9:10pm UTC](https://discourse.julialang.org/t/using-duckdb-appender-with-json-column/129283 "2025-05-31T21:10:39Z")

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Hi all, I’m interested to know if it would be possible to adjust the Appender API in DuckDB to support JSON. Let me explain. As noted here JSON Overview – DuckDB we can create columns with the JSON data type. However, i…

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## [DBInterface prepared statement with named parameters not working](https://discourse.julialang.org/t/dbinterface-prepared-statement-with-named-parameters-not-working/129287)

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**Author:** [@slwu89](https://discourse.julialang.org/u/slwu89)\
**Replies:** 6\
**Last updated:** [May 29, 2025, 1:19am UTC](https://discourse.julialang.org/t/dbinterface-prepared-statement-with-named-parameters-not-working/129287 "2025-05-29T01:19:52Z")

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Based on reading the docs at GitHub - JuliaDatabases/DBInterface.jl: Database interface definitions for Julia, I thought that I could use named parameters in a prepared statement to update data, which did not work. Howev…

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## [Matrix to dataframe conversion with structure of existing dataframe](https://discourse.julialang.org/t/matrix-to-dataframe-conversion-with-structure-of-existing-dataframe/129278)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 4\
**Last updated:** [May 28, 2025, 8:51am UTC](https://discourse.julialang.org/t/matrix-to-dataframe-conversion-with-structure-of-existing-dataframe/129278 "2025-05-28T08:51:46Z")

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Is there any built-in function to convert a matrix to a DataFrame with the structure of a second DataFrame ? i.e. : df = DataFrame(a = \[1,2,3\], b= \["a","b","c"\]) # Option 1, types not promoted dfnames = names(df) m = …

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## [Does DuckDB not allow multiple connections?](https://discourse.julialang.org/t/does-duckdb-not-allow-multiple-connections/128856)

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**Author:** [@slwu89](https://discourse.julialang.org/u/slwu89)\
**Replies:** 3\
**Last updated:** [May 15, 2025, 3:27pm UTC](https://discourse.julialang.org/t/does-duckdb-not-allow-multiple-connections/128856 "2025-05-15T15:27:05Z")

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Hi all. Just curious if I am able to do something like the following MWE. I want to have 2 connections to a relational DB, one of which I can use for R/W and one which is read-only. The read only one I’d like to use FunS…

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