Column Object

This feature will be removed in a future version of Microsoft SQL Server. Avoid using this feature in new development work, and plan to modify applications that currently use this feature.

The Column object represents the properties of a single column in a Microsoft SQL Server table.

SQL-DMO object model that shows the current object

With the Column object, you can:

  • Define columns of a new SQL Server table.

  • Define a new column for an existing SQL Server table.

  • Drop an existing column from a SQL Server table.

  • List the references of a SQL Server column.

The Name property of a Column object uses the SQL Server data type sysname. The Name property must be unique within the names of columns in the SQL Server table.

Column object properties can be set before the Column object is added to the Columns collection of a Table object.

To define columns for a new SQL Server table

  1. Create a Table object.

  2. Set the Name property of the Table object.

  3. Create a Column object.

  4. Set the Name property of the Column object.

  5. Set properties that define the column data type. For example, to specify a column with a char(5) data type, set the Datatype property to char and the Length property to 5.

  6. Set other properties.

  7. Add the Column object to the Columns collection of the Table object.

  8. Repeat Steps from 3 through 7 until all columns are defined.

  9. Add the Table object to the Tables collection of a Database object.

To add a new column to a SQL Server table

  1. Create a Column object.

  2. Set the Name property.

  3. Set properties that define the column data type. For example, to specify a column with a char(5) data type, set the Datatype property to char and the Length property to 5.

  4. Set other properties.

  5. Get the appropriate Table object from the Tables collection of a Database object.

  6. Use the BeginAlter method of the Table object to mark the beginning of changes to the SQL Server table.

  7. Add the Column object to the Columns collection of the Table object.

  8. Use the DoAlter method of the Table object to submit the changed table definition to the instance of SQL Server.

To drop a column from a SQL Server table

  1. Get the appropriate Table object from the Tables collection of a Database object.

  2. Use the BeginAlter method of the Table object to mark the beginning of changes to the SQL Server table.

  3. Get the appropriate Column object from the Columns collection of the Table object.

  4. Use the Remove method of the Column object to drop the column from the SQL Server table.

  5. Use the DoAlter method of the Table object to submit the changed table definition to the instance of SQL Server.

NoteNote

The Column object is compatible with instances of SQL Server version 7.0 and later. However, the Column2 object extends the functionality of the Column object for use with features that were added in SQL Server 2000.

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