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isopen

(Not recommended) Determine if database cursor is open

The isopen function is not recommended. There is no replacement for this functionality. To import data, use the fetch function. For details, see Compatibility Considerations.

Description

example

i = isopen(curs) returns 1 if the database cursor is open and 0 if the database cursor is closed or invalid.

Examples

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Connect to a Microsoft® SQL Server® database and verify the database cursor. Then, import data from the database into MATLAB®. Determine the highest unit cost among the retrieved products in the table. Close the database cursor and database connection.

Create an ODBC database connection to a Microsoft SQL Server database with Windows® authentication. Specify a blank user name and password. The database contains the table productTable.

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

Check the database connection. If the Message property is empty, the connection is successful.

conn.Message
ans =

     []

Create a cursor object by executing an SQL query in the database. Select all the data from the table productTable by using the connection object, and then sort the data by the product number.

sqlquery = 'SELECT * FROM productTable ORDER BY productNumber';
curs = exec(conn,sqlquery);

Determine if the database cursor is open. The isopen function returns the numeric scalar 1, which means the database cursor is open.

i = isopen(curs)
i =

     1

Import data from the executed SQL query and display the first three rows.

curs = fetch(curs);
curs.Data(1:3,:)
ans =

  3×5 table

    productNumber    stockNumber    supplierNumber    unitCost    productDescription
    _____________    ___________    ______________    ________    __________________

    1                4.0035e+05     1001              14          'Building Blocks' 
    2                4.0031e+05     1002               9          'Painting Set'    
    3                  4.01e+05     1009              17          'Slinky'          

Determine the highest unit cost in the table.

data = curs.Data;
max(data.unitCost)
ans =

    24

After you finish working with the cursor object, close it.

close(curs)

Determine if the database cursor is closed. The isopen function returns the numeric scalar 0, which means the database cursor is closed. If the cursor object is invalid, the isopen function returns the same result.

i = isopen(curs)
i =

     0

Close the database connection.

close(conn)

Input Arguments

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Database cursor, specified as a cursor object created using the exec function.

Compatibility Considerations

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Not recommended starting in R2018b

See Also

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External Websites

Introduced in R2015b