MATLAB DATABASE TOOLBOX RELEASE NOTES Guide de l'utilisateur télécharger pdf (Page 516)

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7 Functions — Alphabetical List

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Using DatabaseDatastore Objects

Access collection of data stored in database

MATLAB has various datastores that let you import large data sets into MATLAB for

analysis. A DatabaseDatastore object is a type of datastore that contains the resulting

data from executing an SQL query in a relational database.

With a DatabaseDatastore object, you can perform these tasks:

• Preview data.

• Read data in chunks.

• Read every record in the data set.

• Reset the cursor position to the start of the data set.

• Continue reading data until the cursor position reaches the end of the data set.

• Analyze a large data set stored in a database using MapReduce.

After creating a DatabaseDatastore object, you can write custom functions to run

MapReduce. For details, see “Getting Started with MapReduce”.

Examples

Create a DatabaseDatastore Object

Connect to a Microsoft SQL Server database with Windows Authentication. This code

assumes you are creating a database connection conn using the native ODBC interface

with the authenticated ODBC data source name MS SQL Server Auth and blank user

name and password.

conn = database.ODBCConnection('MS SQL Server Auth','','');

Create a DatabaseDatastore object dbds using the database connection conn and

SQL query sqlquery. This SQL query retrieves all products from the product table

productTable ordered by product number.

sqlquery = ['select * from [toy_store].[dbo].[productTable] '...

'order by productNumber'];

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