MATLAB DATABASE TOOLBOX RELEASE NOTES Guida Utente Scaricare il pdf (Pagina 364)

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101

6 Using Database Toolbox Functions

6-22

Exporting Multiple Records from the MATLAB Workspace

This example does the following:

Imports monthly sales figures for all products from the dbtoolboxdemo data source

into the MATLAB workspace.

Computes total sales for each month.

Exports the totals to a new table.

You use the following Database Toolbox functions:

• fastinsert

• setdbprefs

For details about these functions, see matlab\toolbox\database\dbdemos

\dbinsert2demo.m.

Ensure that the dbtoolboxdemo data source is writable, that is, not read only.

Use the database function to connect to the data source, assigning the returned

connection object as conn. Pass the following arguments to this function:

• dbtoolboxdemo, the name of the data source

• username and password, which are passed as empty strings because no user

name or password is required to access the database

conn = database('dbtoolboxdemo', '', '');

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

details, see database.

Use the setdbprefs function to specify preferences for the retrieved data. Set the

data return format to numeric and specify that NULL values read from the database

are converted to 0 in the MATLAB workspace.

setdbprefs...

({'NullNumberRead';'DataReturnFormat'},{'0';'numeric'})

When you specify DataReturnFormat as numeric, the value for NullNumberRead

must also be numeric.

Import data from the salesVolume table.

curs = exec(conn, 'select * from salesVolume');

1 2 ... 359 360 361 362 363 364 365 366 367 368 369 ... 683 684

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