MATLAB DATABASE TOOLBOX RELEASE NOTES Guide de l'utilisateur télécharger pdf (Page 655)

100

101

setdbprefs

7-225

conn = database('MySQL','username','pwd');

Alternatively, you can use the native ODBC interface for an ODBC connection. For

details, see the database function.

Import data into the MATLAB workspace.

curs = exec(conn,...

'select productnumber,productdescription from producttable');

curs = fetch(curs,3);

curs.Data

ans =

[9] 'Victorian Doll'

[8] 'Train Set'

[7] 'Engine Kit'

Resulting data displays as a cell array.

Change the data return format from cellarray to numeric.

setdbprefs('DataReturnFormat','numeric')

Import data into the MATLAB workspace.

curs = exec(conn,...

'select productnumber,productdescription from producttable');

curs = fetch(curs,3);

curs.Data

ans =

9 NaN

8 NaN

7 NaN

In the database, the values for productDescription are character strings, as seen in

the previous example when DataReturnFormat was set to cellarray. Therefore, the

productDescription values cannot be read when they are imported into the MATLAB

workspace using the numeric format. Therefore, MATLAB treats them as NULL numbers

and assigns them the current value for the NullNumberRead property of NaN.

Change the data return format to structure.

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MATLAB DATABASE TOOLBOX RELEASE NOTES Guide de l'utilisateur Page 655

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