Saving Queries in M-Files
About Generated M-Files
Select Query > Generate
M-File to create an M-file that contains
the equivalent Database Toolbox functions required to run an existing
query that was created in VQB. Edit the M-file to include MATLAB or
related toolbox functions, as needed. To run the query, execute the
M-file.
The following is an example of an M-file generated by VQB.
% Set preferences with setdbprefs.
s.DataReturnFormat = 'cellarray';
s.ErrorHandling = 'store';
s.NullNumberRead = 'NaN';
s.NullNumberWrite = 'NaN';
s.NullStringRead = 'null';
s.NullStringWrite = 'null';
s.JDBCDataSourceFile = '';
s.UseRegistryForSources = 'yes';
s.TempDirForRegistryOutput = '';
setdbprefs(s)
% Make connection to database. Note that the password has been omitted.
% Using ODBC driver.
conn = database('dbtoolboxdemo','','password');
% Read data from database.
e = exec(conn,'SELECT ALL StockNumber,January,February FROM salesVolume');
e = fetch(e);
close(e)
% Close database connection.
close(conn)Back to Top
VQB Query Elements in M-Files
The following VQB query elements do not appear in generated
M-files.
Generated M-files do not include MATLAB workspace
variables to which you assigned query results in the VQB query. The
M-file assigns the query results to e; access these
results using the variable e.Data. For example,
you can add a statement to the M-file that assigns a variable name
to e.Data as follows:
myVar = e.Data
For security reasons, generated M-files do not include
passwords required to connect to databases. Instead, the database statement includes the string 'password' as
a placeholder. To run M-files to connect to databases that require
passwords, substitute your password for the string password in
the database statement.
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 | Importing and Exporting BOOLEAN Data | | Using Database Toolbox Functions |  |
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