Move data from Excel to Access

Step 1: Import data from Excel to Access

Importing data is an operation that can go a lot more smoothly if you take some time to prepare and clean your data. Importing data is like moving to a new home. If you clean out and organize your possessions before you move, settling into your new home is much easier.

Clean your data before you import

Before you import data into Access, in Excel it's a good idea to:

• Convert cells that contain non-atomic data (that is, multiple values in one cell) to multiple columns. For example, a cell in a "Skills" column that contains multiple skill values, such as "C# programming," "VBA programming," and "Web design" should be broken out to separate columns that each contain only one skill value.

• Use the TRIM command to remove leading, trailing, and multiple embedded spaces.

• Remove non-printing characters.

• Find and fix spelling and punctuation errors.

• Remove duplicate rows or duplicate fields.

• Ensure that columns of data do not contain mixed formats, especially numbers formatted as text or dates formatted as numbers.

For more information, see the following Excel help topics:

• Top ten ways to clean your data

• Filter for unique values or remove duplicate values

• Convert numbers stored as text to numbers

• Convert dates stored as text to dates

Choose the best data type when you import

During the import operation in Access, you want to make good choices so that you receive few (if any) conversion errors that will require manual intervention. The following table summarizes how Excel number formats and Access data types are converted when you import data from Excel to Access, and offers some tips on the best data types to choose in the Import Spreadsheet Wizard.

Once the data is in Access, you can delete the Excel data. Don't forget to backup the original Excel workbook first before deleting it.

For more information, see the Access help topic Import or link to data in an Excel workbook.

Automatically append data the easy way

A common problem Excel users have is appending data with the same columns into one large worksheet. For example, you may have an asset tracking solution that started out in Excel but now has grown to include files from many workgroups and departments. This data may be in different worksheets and workbooks, or in text files that are data feeds from other systems. There is no user interface command or easy way to append similar data in Excel.

The best solution is to use Access, where you can easily import and append data into one table by using the Import Spreadsheet Wizard. Furthermore, you can append a lot of data into one table. You can save the import operations, add them as scheduled Microsoft Outlook tasks, and even use macros to automate the process.

Step 2: Normalize data by using the Table Analyzer Wizard

At first glance, stepping through the process of normalizing your data may seem a daunting task. Fortunately, normalizing tables in Access is a process that is much easier, thanks to the Table Analyzer Wizard.

1. Drag selected columns to a new table and automatically create relationships

2. Use button commands to rename a table, add a primary key, make an existing column a primary key, and undo the last action

You can use this wizard to do the following:

• Convert a table into a set of smaller tables and automatically create a primary and foreign key relationship between the tables.

• Add a primary key to an existing field that contains unique values, or create a new ID field that uses the AutoNumber data type.

• Automatically create relationships to enforce referential integrity with cascading updates. Cascading deletes are not automatically added to prevent accidentally deleting data, but you can easily add cascading deletes later.

• Search new tables for redundant or duplicate data (such as the same customer with two different phone numbers) and update this as desired.

• Back up the original table and rename it by appending "_OLD" to its name. Then, you create a query that reconstructs the original table, with the original table name so that any existing forms or reports based on the original table will work with the new table structure.

For more information, see Normalize your data using the Table Analyzer.

Step 3: Connect to Access data from Excel

After the data has been normalized in Access and a query or table has been created that reconstructs the original data, it's a simple matter of connecting to the Access data from Excel. Your data is now in Access as an external data source, and so can be connected to the workbook through a data connection, which is a container of information that is used to locate, log on to, and access the external data source. Connection information is stored in the workbook and can also be stored in a connection file, such as an Office Data Connection (ODC) file (.odc file name extension) or a Data Source Name file (.dsn extension). After you connect to external data, you can also automatically refresh (or update) your Excel workbook from Access whenever the data is updated in Access.

For more information, see Import data from external data sources (Power Query).

Get your data into Access

This section walks you through the following phases of normalizing your data: Breaking values in the Salesperson and Address columns into their most atomic pieces, separating related subjects into their own tables, copying and pasting those tables from Excel into Access, creating key relationships between the newly created Access tables, and creating and running a simple query in Access to return information.

Example data in non-normalized form

The following worksheet contains non-atomic values in the Salesperson column and the Address column. Both columns should be split into two or more separate columns. This worksheet also contains information about salespersons, products, customers, and orders. This information should also be split further, by subject, into separate tables.

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