SQL query in a M-file. Not working

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Kallam Haranadha Reddy 2016-8-3

0
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https://ww2.mathworks.cn/matlabcentral/answers/298301-sql-query-in-a-m-file-not-working

评论： Kallam Haranadha Reddy 2016-8-7

I tried to execute an sql query from an M- file. But I am getting the error message "undefined function fetch ". when i executed the same query from workspace it is working.

I tried the following code in a M-file:

function [ Pocc ] = Multiprodinv( x )
%UNTITLED Summary of this function goes here
%   Detailed explanation goes here
conn = database('MultiProductInventory','','');
x1=x(1);
x2=x(2);
x3=x(3);
x4=x(4);
x5=x(5);
x6=x(6);
x7=x(7);
x8=x(8);
x9=x(9);
x10=x(10);
curs = exec(conn,['select all ID from Stocks where PI=',num2str(x1),'and F1=',num2str(x2),...
    'and F2=',num2str(x3),'and F3=',num2str(x4),'and F4=',num2str(x5),'and F5=',num2str(x6),...
    'and F6=',num2str(x7),'and F7=',num2str(x8),'and F8=',num2str(x9),'and F9=',num2str(x10)]);
curs=fetch(curs);
y= curs.Data;
Pocc=length(y);

x is a record of integer values with 10 fields representing the inventory at various levels (plants, warehouses, distributors, agents etc).The first field of x is the ProductID. The program has to find the number of occurrences of the record x in the database(MultiProductInventory) table Stocks.

please guide me.

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Guillaume 2016-8-3

在 MATLAB Online 中打开

You've got a computer language that allows you to automate things, and instead you go and make it more manual by typing every step of your query.

conn = database('MultiProductInventory','','');
query = ['select all ID from Stocks where PI=', num2str(x(1))];
for fidx = 1:9
   query = [query, sprintf(' and F%d = ', fidx), num2str(x(fidx + 1))];
end
curs = exec(conn, query);

Isn't that less work?

No idea about your problem, though. Can you give the entire error message? Are you sure that curs is a cursor object when you call fetch from the command line?

Kallam Haranadha Reddy 2016-8-7

I searched for MATLAB questions and answers for my problem ( SQL query not working in M file) ( error message : function fetch not defined). I am providing the link below to a similar problem where fetch is not working and runsqlscript command is working. I am using Micro soft's Access database.I am a novice to database. In the link given below , in the 'conn' ( connection to database), he has used database name, user name, password and JDBC address. I searched the MATLAB documentation for MS-Access database driver address. But i could not find it, instead there are details about oracle, SQL server and MYsql databases. i want to know whether there is any syntax error in my coding or i have to specify Access database driver address or the MATLAB does not support Access database But then, i am surprised, why the same sequence of commands, when executed from command line, are giving the results.

please guide me.

http://in.mathworks.com/matlabcentral/answers/263828-why-does-fetch-command-for-sql-query-fail-but-runsqlscript-work

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