database.fetch - Execute SQL statement to import data into MATLAB workspace

Syntax

results = fetch(conn, sqlquery) results = fetch(conn, sqlquery, RowInc)

Description

results = fetch(conn, sqlquery) executes the SQL statement sqlquery, imports data for the open connection object conn, and returns the data to results. (For more information on SQL statements, see exec.)

results = fetch(conn, sqlquery, RowInc) imports RowInc rows of data at a time.

Input Arguments

`conn`	A database connection object.
`sqlquery`	A SQL statement.
`RowInc`	Specifies the number of rows of data to import at a time. Use `RowInc` when importing large amounts of data. Retrieving data in increments, as specified by `RowInc`, helps reduce overall retrieval time.

Output Arguments

results

A cell array, structure, or numeric matrix, depending on specifications set by setdbprefs.

Tips

As shown in the syntax section above, you call the database.fetch function with the command fetch rather than database.fetch. You implicitly call database.fetch by passing a database object, conn, to the function fetch. Fetch also works with a cursor object. See cursor.fetch.
The order of records in your database does not remain constant. Use the SQL ORDER BY command in your sqlquery statement to sort data.

Examples

This example shows how to import data. (If you experience speed and memory issues, use the rowinc argument

Import the country column from the customers table in the SampleDB database.

conn = database('SampleDB','','');
setdbprefs('DataReturnFormat','cellarray')
results = fetch(conn, 'select country from customers')

results = 

    'Germany'
    'Mexico'
    'Mexico'
    'UK'
    'Sweden'

    ...

    'Finland'
    'Brazil'
    'USA'
    'Finland'
    'Poland'

View the size of the cell array into which the results were returned.
```
size(results)ans =

    91     1
```

Import two columns of data and view information about the data.

Import the ProductName and Discontinued columns from the SampleDB database.

conn = database('SampleDB', '', '');
setdbprefs('DataReturnFormat','cellarray')
results = fetch(conn, ['select ProductName, '...
   'Discontinued from Products']);

View the size of the cell array into which the results were returned.
```
size(results)
ans =

    77   2
```
View the results for the first row of data.
```
results(1,:)
ans = 
    'Chai'    [0]
```
View the data type of the second element in the first row of data.
```
class(results{1,2})
ans =
logical
```