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reset

Reset DatabaseDatastore to initial state

Syntax

reset(dbds)

Description

example

reset(dbds) resets the DatabaseDatastore object dbds to the state where no data has been read from it. Resetting allows re-reading from the same DatabaseDatastore.

Examples

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Using a JDBC driver, create a database connection to a Microsoft® SQL Server® database with Windows® authentication. Specify a blank user name and password. The code assumes that you are connecting to database toy_store, database server dbtb04, and port number 54317.

conn = database('toy_store','','','Vendor','Microsoft SQL Server', ...
    'Server','dbtb04','PortNumber',54317,'AuthType','Windows');

Create a DatabaseDatastore object using the database connection and SQL query. This SQL query retrieves all data from the table. Specify reading a maximum of 10 records from the executed SQL query when using the read function.

sqlquery = 'select * from airlinesmall';

dbds = databaseDatastore(conn,sqlquery,'ReadSize',10);

Read data from the start of the data set.

read(dbds)
ans = 

    Year    Month    DayofMonth    DayOfWeek    DepTime    CRSDepTime    ArrTime    CRSArrTime    UniqueCarrier    FlightNum    TailNum    ActualElapsedTime    CRSElapsedTime    AirTime    ArrDelay    DepDelay    Origin    Dest     Distance    TaxiIn    TaxiOut    Cancelled    CancellationCode    Diverted    CarrierDelay    WeatherDelay    NASDelay    SecurityDelay    LateAircraftDelay
    ____    _____    __________    _________    _______    __________    _______    __________    _____________    _________    _______    _________________    ______________    _______    ________    ________    ______    _____    ________    ______    _______    _________    ________________    ________    ____________    ____________    ________    _____________    _________________

    1987    10       28            3            1140       1140          1212       1215          'US'             262          'NA'       32                    35               'NA'        -3          0          'CLE'     'PIT'    105         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10        9            5            1155       1155          1250       1300          'US'             282          'NA'       55                    65               'NA'       -10          0          'ROC'     'LGA'    254         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10       22            4             715        715           807        803          'US'             304          'NA'       52                    48               'NA'         4          0          'DTW'     'PIT'    201         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10       16            5            1553       1555          1641       1640          'US'             323          'NA'       48                    45               'NA'         1         -2          'BUF'     'PIT'    186         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10       30            5            1821       1815          1956       1955          'US'             346          'NA'       95                   100               'NA'         1          6          'IND'     'EWR'    644         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10       12            1            1300       1300          1529       1528          'US'             370          'NA'       89                    88               'NA'         1          0          'STL'     'PIT'    553         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10        7            3             810        810           904        900          'US'             387          'NA'       54                    50               'NA'         4          0          'ELM'     'PIT'    208         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10       19            1             733        735           827        831          'US'             407          'NA'       54                    56               'NA'        -4         -2          'ROC'     'CLE'    245         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10       15            4             828        830           916        921          'US'             424          'NA'       48                    51               'NA'        -5         -2          'ORF'     'PHL'    211         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10        4            7            1750       1735          1837       1816          'US'             449          'NA'       47                    41               'NA'        21         15          'PIT'     'CLE'    105         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             

read returns the first 10 records in the data set.

Reset the DatabaseDatastore object to the state where no data has been read from it. Resetting allows rereading from the same DatabaseDatastore object.

reset(dbds)

Read data from the start of the data set.

read(dbds)
ans = 

    Year    Month    DayofMonth    DayOfWeek    DepTime    CRSDepTime    ArrTime    CRSArrTime    UniqueCarrier    FlightNum    TailNum    ActualElapsedTime    CRSElapsedTime    AirTime    ArrDelay    DepDelay    Origin    Dest     Distance    TaxiIn    TaxiOut    Cancelled    CancellationCode    Diverted    CarrierDelay    WeatherDelay    NASDelay    SecurityDelay    LateAircraftDelay
    ____    _____    __________    _________    _______    __________    _______    __________    _____________    _________    _______    _________________    ______________    _______    ________    ________    ______    _____    ________    ______    _______    _________    ________________    ________    ____________    ____________    ________    _____________    _________________

    1987    10       28            3            1140       1140          1212       1215          'US'             262          'NA'       32                    35               'NA'        -3          0          'CLE'     'PIT'    105         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10        9            5            1155       1155          1250       1300          'US'             282          'NA'       55                    65               'NA'       -10          0          'ROC'     'LGA'    254         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10       22            4             715        715           807        803          'US'             304          'NA'       52                    48               'NA'         4          0          'DTW'     'PIT'    201         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10       16            5            1553       1555          1641       1640          'US'             323          'NA'       48                    45               'NA'         1         -2          'BUF'     'PIT'    186         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10       30            5            1821       1815          1956       1955          'US'             346          'NA'       95                   100               'NA'         1          6          'IND'     'EWR'    644         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10       12            1            1300       1300          1529       1528          'US'             370          'NA'       89                    88               'NA'         1          0          'STL'     'PIT'    553         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10        7            3             810        810           904        900          'US'             387          'NA'       54                    50               'NA'         4          0          'ELM'     'PIT'    208         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10       19            1             733        735           827        831          'US'             407          'NA'       54                    56               'NA'        -4         -2          'ROC'     'CLE'    245         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10       15            4             828        830           916        921          'US'             424          'NA'       48                    51               'NA'        -5         -2          'ORF'     'PHL'    211         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             
    1987    10        4            7            1750       1735          1837       1816          'US'             449          'NA'       47                    41               'NA'        21         15          'PIT'     'CLE'    105         'NA'      'NA'       0            'NA'                0           'NA'            'NA'            'NA'        'NA'             'NA'             

read again returns the first 10 records in the data set.

Close the DatabaseDatastore object and the database connection.

close(dbds)

Input Arguments

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Datastore containing data in a database, specified as a DatabaseDatastore object created using the databaseDatastore function.

Introduced in R2014b