Loading multiple files into the same database

Question

Bob Choy 2012-12-16

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Hi! I have the folowing function:

function loaddatabase(Name_File,Namedb)
  id = fopen(Name_File, 'r');
  create = 'create table Table1 ( Temperature integer, Humidity real, PRIMARY KEY(Temperature) );';
  sqlite(create,Namedb);
  while ~feof(id) 
    temperature = fscanf (id, '%d', 1);
    humidity = fscanf (id, '%f\n',1);
    insert = sprintf('insert into Table1 values ( %d, %f );', temperature, humidity);
    sqlite(insert,Namedb);
  end
end

This function creates a database from information contained a .txt file. Where Name_File is the name of that .txt file and Namedb is the name I want to give my database. My .txt files follow the following structure: file1.txt, file2.txt, etc...

My problem is that I don't want load the info of a single .txt file but rather all of them into the same database.

How can I do this?

Thank you in advance.

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Answer 1

Mark Whirdy 2012-12-16

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编辑：Mark Whirdy 2012-12-16

Hi Bob

Can you read the contents of all files into matlab in loop, vertically concatenating the cellarrays and perform a single fastinsert (of the vertcatted cellarray) at the end? If I'm missing the crux of the issue here, could you provide some more code to make the context clearer?

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Bob Choy 2012-12-16

Im not sure what your first question was, can you type that into code so I can understand it better? I also updated the code so its hopefully clearer now.

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Answer 2

Mark Whirdy 2012-12-16

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https://ww2.mathworks.cn/matlabcentral/answers/56729-loading-multiple-files-into-the-same-database#answer_68669

在 MATLAB Online 中打开

In semi-pseudo code below

My_array = []; % container for all file contents
for i = 1:size(Name_File_Array)
fid = fopen(Name_File_Array{i,:}, 'r');
str = fread(fid, '*char')'; % whatever parsing is suitable for your data, since I can't see your data I have no idea what
My_array = [My_array;str]; % vertcat each file contents into a single large array
exec('Create table mytable(header1,header2,header3)');
fastinsert('mytable',My_array)
end

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Bob Choy 2012-12-16

在 MATLAB Online 中打开

My data follows the following structure:

integer  real
integer  real
integer  real

And so on. Where the first column are temperature values and the second humidity values. Does this help you understand how can I do this using my function above?

Thank you for your efforts so far.

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