attr

(Removed) Retrieve attributes of columns in fetched data set

The attr function has been removed. There is no replacement for this functionality. To import data, use the fetch function. For details, see Compatibility Considerations.

Syntax

attributes = attr(curs)

attributes = attr(curs,colnum)

Description

attributes = attr(curs) retrieves attribute information for all columns in the fetched data set curs.

attributes = attr(curs,colnum) retrieves attribute information for the column number colnum in the fetched data set curs.

Examples

Retrieve Attribute Data for a Fetched Data Set

Create the database connection conn to an Oracle^® database using an ODBC connection. This code assumes that you are connecting a data source named dbname with user name username and password pwd. The data source identifies an Oracle database that contains the table inventoryTable with these columns: productNumber, Quantity, Price, and inventoryDate.

conn = database(dbname,username,pwd);

Import all the data from the table inventoryTable. The cursor object curs contains the executed query. Import the data from the executed query using the fetch function.

sqlquery = 'SELECT * FROM inventoryTable';

curs = exec(conn,sqlquery);
curs = fetch(curs);

Retrieve attribute information for all the fetched data using curs.

attributes = attr(curs)

attributes = 

1x4 struct array with fields:

    fieldName
    typeName
    typeValue
    columnWidth
    precision
    scale
    currency
    readOnly
    nullable
    Message

attributes contains a structure array for three columns in the table inventoryTable.

Display the attribute data for the first column in the table inventoryTable.

attributes(1)

ans = 

      fieldName: 'PRODUCTNUMBER'
       typeName: 'NUMBER'
      typeValue: 2.00
    columnWidth: 39.00
      precision: 38.00
          scale: 0
       currency: 'true'
       readOnly: 'false'
       nullable: 'true'
        Message: []

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

close(curs)
close(conn)

Input Arguments

curs — Database cursor

cursor object

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

colnum — Column number

numeric scalar

Column number, specified as a numeric scalar to denote the column in the fetched data set curs for retrieving attribute information.

Data Types: double

Output Arguments

attributes — Attribute data

structure array

Attribute data, returned as a structure array containing attribute information for each column in the fetch data set curs. The following attributes are available.

Attribute	Description
fieldName	Name of the column.
typeName	Data type.
typeValue	Numerical representation of the data type.
columnWidth	Size of the field.
precision	Precision value for floating and double data types; an empty value is returned for character vectors or string scalars.
scale	Precision value for real and numeric data types; an empty value is returned for character vectors or string scalars.
currency	If this attribute equals true, the data format is currency.
readOnly	If this attribute equals true, the data cannot be overwritten.
nullable	If this attribute equals true, the data can be NULL.
Message	Error message returned by fetch.

Version History

Introduced before R2006a

R2022a: attr function has been removed

Errors starting in R2022a

The attr function has been removed. Use the fetch function to import data. Some differences between the workflows might require updates to your code.

Update Code

Use the fetch function with the connection object to import data from a database in one step.

In prior releases, you wrote multiple lines of code to create the cursor object, import data, and find the attributes of the database columns. For example:

curs = exec(conn,sqlquery);
curs = fetch(curs);
results = curs.Data;
attributes = attr(curs);
close(curs)

Now you can import data in one step using the fetch function.

results = fetch(conn,sqlquery);

If you return imported data as a table, access details about the variables in the table by using a function such as summary.

There is no replacement functionality for the attr function.