Review Data Type Mapping (SQL Server Import and Export Wizard)

If you specified a data type mapping that may not succeed in the Mappings list of the Column Mappings dialog box, the SQL Server Import and Export Wizard shows the Review Data Type Mapping page. On this page, you review detailed information about data type conversions that the wizard has to perform to make the source data compatible with the destination. This information includes visual cues to distinguish data type conversions that are expected to succeed from conversions that may cause errors or truncations. For each conversion, you decide whether to accept the conversion that the wizard suggests, and you specify how to handle any errors that may occur.

Tip

You can't change data type mappings on the Review Data Type Mapping page. However, you can click Back to return to the Select Source Tables and Views page, and then click Edit Mappings to open the Column Mappings dialog box again. In the Column Mappings dialog box, you can specify data type mappings that are more likely to succeed. To take another look at the Column Mappings dialog box, see Column Mappings.

Screen shot of the Review Data Type Mapping page

The following screen shot shows an example of the Review Data Type Mapping page of the wizard.

In this example:

  • The user has specified a mapping in the Column Mappings dialog box that may not succeed.
  • The warning icon on the row in the Table list indicates that there is a problem converting at least one column of data from the query results to a compatible data type in the destination table.
  • The warning icon on the first row in the Data type mapping list indicates that the mapping from the int data type of the source column to the smalldatetime data type of the destination column may cause a loss of data.

    Review Data Type Mapping page of the Import and Export Wizard

Review the source and destination tables

The upper section of the Review Data Type Mapping page is a Table list that lists the tables to be copied from the source to the destination. To see conversion information about an individual table, select a table in the Table list. The conversion information for the individual columns of the selected table appears in the lower part of the page in the Data type mapping grid.

In this example, the results of the query that the user provided will be copied to the Sales.CustomerNew2 table at the destination. The warning icon indicates that there is a problem converting at least one column of data from the query results to a compatible data type in the destination table.

Review mapping - tables

The following table describes the columns in the Table list.

Column Description
(Source icon) Indicates the probability of success for the data type conversions:
- A green check mark icon indicates that the wizard expects all data type conversions for this table to succeed.
- A yellow warning icon indicates that you should review the individual conversions that the wizard will perform. To review these conversions, select the table, and then review the conversions for individual columns in the Data type mapping list.
- A red error icon indicates that the wizard is not able to perform some of the conversions for this table reliably.
Source The name of the source table.
(Destination icon) Indicates whether the destination already exists or will be created by the wizard:
- A table icon indicates that the destination is an existing table.
- A table icon with a sunburst indicates that the destination is a new table that the wizard will create.
Destination The name of the destination table.

Review the data type mappings

The middle section of the Review Data Type Mapping page is the Data type mapping list. This grid provides detailed conversion information about the columns in the source table that's selected in the Table list in the upper part of the page.

In this example, each column at the source will be copied to a column with the same name and data type at the destination. The warning icon on the first row in the Data type mapping list indicates that the mapping from the int data type of the source column to the smalldatetime data type of the destination column may cause a loss of data.

Review mapping - mappings

The following table describes the columns in the Data type mapping list.

Column Description
(Conversion icon) Indicates the probability of success for the data type conversions:
- A green check mark icon indicates that the wizard expects the data type conversion for this column to succeed.
- A yellow warning icon indicates that you should review the conversion that the wizard will perform. To review the conversion, double-click on the column to view the Column Conversion Details dialog box. For more info, see Column Conversion Details Dialog Box.
- A red error icon indicates that the wizard is not able to perform the conversion reliably.
Source Column The name of the source column.
Source Type The data type of the source column.
Destination Column The name of the destination column.
Destination Type The data type of the destination column.
Convert Specify whether to continue with the planned conversion:
- Select the check box to have the wizard continue with the planned conversion.
- Clear the check box to cancel the data type conversion.
On Error Specify how the wizard handles errors:
- Use the On Error (global) setting, which you can specify at the bottom of this page.
- Fail with an error, and stop the import or export process.
- Ignore the error.
On Truncation Specify how the wizard handles truncation:
- Use the On Truncation (global) setting, which you can specify at the bottom of this page.
- Fail with an error, and stop the import or export process
- Ignore the truncation.
Tip

To see detailed information about the conversion of a particular column of data, double-click any row in the list. The Column Conversion Details dialog box opens and displays more detailed conversion information for the column. For more info, see Column Conversion Details Dialog Box.

Specify global error handling options

The lower section of the Review Data Type Mapping page lets you specify error handling options that apply by default to all columns. These settings apply to all conversions that have Use Global selected in the On Error or On Truncation columns of the Data type mapping list.

This example shows the default values for the two global error handling options.

Review mapping - errors

On Error (global)
Specify how the wizard handles errors:

  • Fail with an error, and stop the import or export process. This is the default value.
  • Ignore the error, and continue the import or export process.

    On Truncation (global)
    Specify how the wizard handles data truncation:

  • Fail with an error, and stop the import or export process. This is the default value.
  • Ignore the truncation, and continue the import or export process.

What's next?

After you review the warnings, specify conversion options, and specify how to handle errors, the Review Data Type Mapping page takes you back to the Column Mappings dialog box. For more info, see Column Mappings.

See also

Data Type Mapping in the SQL Server Import and Export Wizard