attr

(Not recommended) Retrieve attributes of columns in fetched data set

The attr function is not recommended. 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

example

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

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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

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`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

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`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`.

Compatibility Considerations

expand all

`attr` function is not recommended

Not recommended starting in R2018b

The attr function is not recommended. Use the fetch function to import data. Some differences between the workflows might require updates to your code.

There are no plans to remove the attr function at this time.

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.

Documentation

attr

Syntax

Description

Examples

Retrieve Attribute Data for a Fetched Data Set

Input Arguments

`curs` — Database cursor
`cursor` object

`colnum` — Column number
numeric scalar

Output Arguments

`attributes` — Attribute data
structure array

Compatibility Considerations

`attr` function is not recommended

See Also

Database Toolbox Documentation

Support

Documentation

attr

Syntax

Description

Examples

Retrieve Attribute Data for a Fetched Data Set

Input Arguments

curs — Database cursor cursor object

colnum — Column number numeric scalar

Output Arguments

attributes — Attribute data structure array

Compatibility Considerations

attr function is not recommended

See Also

Database Toolbox Documentation

Support

`curs` — Database cursor
`cursor` object

`colnum` — Column number
numeric scalar

`attributes` — Attribute data
structure array

`attr` function is not recommended