Columns

To access metadata for the columns available in the database, retrieve the Columns schema collection. You can also access the column metadata for views by retrieving the ViewColumns schema collection.

Alternatively, retrieve metadata from Result Sets. The same columns are returned for result set metadata as the Columns and ViewColumns schema collections; see below.

Retrieving Column Metadata

Call the GetSchema method of the CompositeConnection class to retrieve the Columns or ViewColumns schema collections. You can restrict results by table name, as shown in the example below.

 

C#

 

string connectionString = "Host=myHost;Domain=myDomain;DataSource=myDataSource;User=myUser;Password=myPassword";

using (CompositeConnection conn = new CompositeConnection(connectionString)) {

  conn.Open();

  DataTable databaseSchema = conn.GetSchema("Columns", new string[] {"Products"});

  foreach (DataRow column in databaseSchema.Rows) {

    Console.WriteLine(column["COLUMN_NAME"]);

    Console.WriteLine(column["IS_KEY"]);

    Console.WriteLine(column["DATA_TYPE"]);

  }

}

VB.NET

 

Dim connectionString As String = "Host=myHost;Domain=myDomain;DataSource=myDataSource;User=myUser;Password=myPassword"

Using conn As New CompositeConnection(connectionString)

  conn.Open()

  Dim databaseSchema As DataTable = conn.GetSchema("Columns", New String() {"Products"})

  For Each column As DataRow In databaseSchema.Rows

    Console.WriteLine(column("COLUMN_NAME"))

    Console.WriteLine(column("IS_KEY"))

    Console.WriteLine(column("DATA_TYPE"))

  Next

End Using

Columns Returned

The Columns and ViewColumns schema collections and DataTables returned from the query contain the following columns.

 

Column Name	Data Type	Description
TABLE_CATALOG	System.String	The database containing the table.
TABLE_SCHEMA	System.String	The schema containing the table.
TABLE_NAME	System.String	The table containing the column.
COLUMN_NAME	System.String	The column name.
ORDINAL_POSITION	System.Int32	The sequence number of the column.
COLUMN_DEFAULT	System.String	The default value of the column.
IS_NULLABLE	System.String	Whether the column allows null values. This value is YES or NO.
DATA_TYPE	System.String	The column data type.
CHARACTER_MAXIMUM_LENGTH	System.Int32	The maximum length in characters of a column with character data.
NUMERIC_PRECISION	System.Int32	The maximum number of digits allowed for numeric data.
NUMERIC_SCALE	System.Int32	The maximum column scale or the number of digits to the right of the decimal point in numeric data.
DATETIME_PRECISION	System.Int32	Returns the precision in fractional seconds if the parameter type is datetime or smalldatetime. Otherwise, returns NULL.
CHARACTER_SET_NAME	System.String	The name of the character set for a column with character data.
COLUMN_COMMENT	System.String	A brief description of the column.
IS_KEY	System.Boolean	Whether the column is the primary key of the table referenced by TABLE_NAME.
IS_READONLY	System.Boolean	Whether the column is read-only.
PROVIDER_TYPE	System.Type	Indicates the appropriate data type dependent on the language you are executing in.