matlab cannot find the datainsert function

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James Johnson 2018-1-18

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/377696-matlab-cannot-find-the-datainsert-function

编辑： James Johnson 2018-1-27

I confirmed that I have Matlab's Database Toolbox. I also reinstalled the latest matlab R2017b because it didn't work with 2017a. It looks like Matlab might have a pretty serious bug, or maybe I'm doing something wrong. This is my first time trying. Here is what I do and the errors I get:

>> help datainsert
datainsert not found.
Use the Help browser search field to search the documentation, or type "help help" for help command options, such as help for methods.

That's already weird then I do:

>> conn=sqlite('test.db','create')
conn = 
    sqlite with properties:
        Database: 'test.db'
          IsOpen: 1
      IsReadOnly: 0
>> exec(conn,'create table TestTable (IDtest NUMERIC, data_test NUMERIC)')
>> datainsert(conn,'TestTable','IDtest',1)
Undefined function or variable 'datainsert'.

Just so you can see that I have everything installed here is the output of my ver command:

>> ver
-----------------------------------------------------------------------------------------------------
MATLAB Version: 9.3.0.713579 (R2017b)
MATLAB License Number: XXXXX
Operating System: Microsoft Windows 10 Pro Version 10.0 (Build 16299)
Java Version: Java 1.8.0_121-b13 with Oracle Corporation Java HotSpot(TM) 64-Bit Server VM mixed mode
-----------------------------------------------------------------------------------------------------
MATLAB                                                Version 9.3         (R2017b)
Simulink                                              Version 9.0         (R2017b)
Bioinformatics Toolbox                                Version 4.9         (R2017b)
Communications System Toolbox                         Version 6.5         (R2017b)
Computer Vision System Toolbox                        Version 8.0         (R2017b)
Control System Toolbox                                Version 10.3        (R2017b)
Curve Fitting Toolbox                                 Version 3.5.6       (R2017b)
DSP System Toolbox                                    Version 9.5         (R2017b)
Data Acquisition Toolbox                              Version 3.12        (R2017b)
Database Toolbox                                      Version 8.0         (R2017b)

FYI datainsert is a built-in (not user-defined) function: https://www.mathworks.com/help/database/ug/datainsert.html

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Answer 1

James Johnson 2018-1-18

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https://ww2.mathworks.cn/matlabcentral/answers/377696-matlab-cannot-find-the-datainsert-function#answer_300774

在 MATLAB Online 中打开

2 relevant details came up when Mathworks resolved the issue.

1) datainsert is not on the path until the user calls the "database function: so the following code gets it to appear:

>>database;
>> help datainsert
--- help for database.jdbc.connection/datainsert ---
   datainsert Export MATLAB data into database table.

2) Mathworks changed the folder where the functions are stored. In the 2015b installation I have on one computer they are in: C:\Program Files\MATLAB\R2015b\toolbox\database\database\

now they are in:

C:\Program Files\MATLAB\R2017b\toolbox\database\database\+database\+jdbc\@connection

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Arthur Goldsipe 2018-1-18

I'd like to clarify some details and answer the question in your comment on my proposed answer.

As you discovered, the implementation of datainsert changed between R2015b and R2017b. It was a standalone function in R2015b, but it's now an object method in R2017b. Many times, those details don't matter. But the help method is a case where this difference matters.

The help command only looks for methods for objects you've actually used in this MATLAB session. Before you create a database object, help datainsert returns nothing. After you create a database object, help datainsert returns the information you're looking for. Nothing gets downloaded to make this happen. It's just that the help system gets the hint it needs to figure out where to look for the datainsert help.

However, you can always access the datainsert help by fully specifying that it's a method of the database object: help database.jdbc.connection/datainsert. However, I usually just search for help using the doc command, which does not suffer from this limitation. If you type doc datainsert, you should find the information you're looking for.

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Answer 2

Arthur Goldsipe 2018-1-18

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Hi,

I think you need to use insert instead of datainsert. The Database Toolbox offers two different ways of working with sqlite databases. insert is the command to use when the connection is created using sqlite; datainsert is the command to use when the connection is created using database. You can read more about the two different approaches here .

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James Johnson 2018-1-18

编辑：James Johnson 2018-1-27

Thanks, that may offer a path forward for today. Is the fact that the datainsert function is missing a separate issue or is it related? For example, does matlab refrain from downloading datainsert until a person creates a database using the "database" function?

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