Select Source Tables and Views (SQL Server Import and Export Wizard)
After you specify that you want to copy an entire table, or after you provide a query, the SQL Server Import and Export Wizard shows Select Source Tables and Views. On this page, you select the existing tables and views that you want to copy. Then you map the source tables to new or existing destination tables. Optionally, you also review the mapping of individual columns and preview sample data.
If you have to copy more than one SQL Server database, or SQL Server database objects other than tables and views, use the Copy Database Wizard instead of the Import and Export Wizard. For more info, see Use the Copy Database Wizard.
Screen shot - If you're going to copy tables
The following screen shot shows an example of the Select Source Tables and Views page of the wizard when you previously selected the Copy data from one or more tables or views option on the Specify Table Copy or Query page. In the list you see all the tables and views available from the data source.
In this example, the Source list contains all the tables in the AdventureWorks sample database. The selected row shows that the user wants to copy the Sales.Customer table from the source to the new Sales.CustomerNew table at the destination.
Screen shot - If you provided a query
The following screen shot shows an example of the Select Source Tables and Views page of the wizard when you previously selected the Write a query to specify the data to transfer option on the Specify Table Copy or Query page. The Source list contains only a single row, where the item named
[Query] represents the query that you provided on the Provide a Source Query page.
In this example, the user wants to copy the query results from the source to the Sales.CustomerNew table at the destination.
Select source and destination tables
Using the check boxes, select from the list of available tables and views to copy to the destination. By default, data from the data source is copied without changes. If you create a new destination table, the schema for the new table - that is, the list of columns and their properties - is also copied without change from the data source.
If you provided a query, the list contains only one item with the name
Select a destination table from the list for each source table or query, or enter the name of a new table that you want the wizard to create. If you select an existing destination table, the table has to have columns with data types that are compatible with the source data.
If you pause at this point in the wizard to create a new table manually in the destination database by using an external tool (such as SQL Server Management Studio), the new table is not immediately visible in the list of available destination tables. To refresh the list of destination tables, step back to the Choose a Destination page, re-select the destination database to refresh the list of available tables and views, and then step forward again to the Select Source Tables and Views page.
Optionally, review column mappings and preview data
Optionally, click Edit mappings to display the Column Mappings dialog box for the selected table. Use the Column Mappings dialog box to do the following things,
- Review the mapping of individual columns between the source and the destination.
- Copy only a subset of columns by selecting ignore for columns that you don't want to copy.
For more info, see Column Mappings.
Optionally, click Preview to preview up to 200 rows of sample data in the Preview Data dialog box. This confirms that the wizard is going to copy the data that you want to copy. For more info, see Preview Data.
After you preview the data, you may want to change the options that you selected on previous pages of the wizard. To make these changes, return to the Select Source Tables and Views page, and then click Back to return to previous pages where you can change your selections.
Select source and destination tables for Excel
Excel source tables
The list of source tables and views for an Excel data source includes two types of Excel objects.
- Worksheets. Worksheet names are followed by the dollar sign ($) - for example, 'Sheet1$'.
- Named ranges. Named ranges, if any, are listed by name.
If you want to load data from or to a specific, unnamed range of cells - for example, from or to [Sheet1$A1:B4], you have to write a query. Step back to the Specify Table Copy or Query page and select Write a query to specify the data to transfer.
Prepare the Excel source data
Whether you specify a worksheet or a range as the source table, the driver reads the contiguous block of cells starting with the first non-empty cell in the upper-left corner of the worksheet or range. As a result, you can't have empty rows in the source data. For example, you can't have an empty row between the column headers and the data rows. If you have a title followed by empty rows at the top of the worksheet above your data, you can't query the worksheet. In Excel, you have to assign a name to your range of data, and query the named range instead of the worksheet.
Excel destination tables
If you are exporting data to Excel, you can specify the destination in one of the following three ways.
- Worksheet. To specify a worksheet, append the $ character to the end of the sheet name and add delimiters around the string - for example, [Sheet1$].
- Named range. To specify a named range, simply use the range name - for example, MyDataRange.
- Unnamed range. To specify a range of cells that you haven't named, append the $ character to the end of the sheet name, add the range specification, and add delimiters around the string - for example, [Sheet1$A1:B4].
Special considerations for Excel sources and destinations
When you're using Excel as a source or destination, it's a good idea to click Edit Mappings and to review the data type mappings on the Column Mappings page.
Data types in Excel workbooks. Excel is not a typical database. Its columns do not have fixed data types. The wizard recognizes only a limited set of data types in Excel - numeric, currency, Boolean, date/time, string (255 characters or less), and memo (more than 255 characters). The wizard samples a certain number of rows (by default, the first eight rows) in an existing Excel data source to guess at the data type of each column.
When the wizard has to do explicit data type conversions to load from or to Excel, it typically displays the Review Data Type Mapping page where you can review those conversions. These conversions may include the following.
- Conversion between double-precision Excel numeric columns and numeric columns of other types.
- Conversion between 255-character Excel string columns and string columns of different lengths.
- Conversion between Unicode Excel string columns and non-Unicode string columns that use specific codepages.
Special considerations for Excel sources
Null or missing values in imported data. When an Excel column appears to contain mixed data types in the first eight rows sampled by the wizard - for example, numeric values mixed with text values - the wizard picks the majority data type as the data type of the column, and returns null values for cells that contain data of other types. There is no way to change this behavior of the wizard.
Truncated strings in imported data. When the wizard determines that an Excel column contains text data, the wizard picks the data type of the column - string or memo - based on the longest value that it samples in the first eight rows. If the wizard doesn't find any values longer than 255 characters in the rows that it samples, it treats the column as a 255-character string column instead of a memo column, and truncates values longer than 255 characters. To import data from a memo column without truncation, you have to make sure that the memo column contains at least one value longer than 255 characters in the first eight rows that are sampled by the wizard.
Special considerations for Excel destinations
Specifying an existing range. When you specify an existing range as the destination, you get an error if the range has fewer columns than the source data. However, if the range that you specify has fewer rows than the source data, the wizard continues writing rows and extends the range definition to match the new number of rows.
Saving memo (ntext) data. Before you can successfully save strings longer than 255 characters to an Excel column, the wizard has to recognize the data type of the destination column as memo and not string.
- If the destination table already contains rows of data, the first eight rows that are sampled by the wizard have to contain at least one row with a value longer than 255 characters in the memo column.
- If the destination table is created by the wizard, the CREATE TABLE statement must use LONGTEXT (or one of its synonyms) as the data type of the the memo column. Check the CREATE TABLE statement and revise it, if necessary, by clicking Edit SQL next to the Create destination table option on the Column Mappings page.
After you select the existing tables and views to copy and map them to their destinations, the next page is Save and Run Package. On this page, you specify whether you want to run the copy operation immediately. Depending on your configuration, you may also be able to save the SQL Server Integration Services package created by the wizard to customize it and to reuse it later. For more info, see Save and Run Package.