Question

Set the primary key for the Department table. With the Department table in Design View, select the deptCode field and then click on the Primary Key button. When done successfully you will see the deptCode field with a key icon beside it: If MS Access rejects your primary key then you must examine the values you previously entered for deptCode - there must be some duplicated value. If this happens you must view the table in Datasheet View and find the duplicated value and make necessary changes. Once MS Access has accepted your primary key you should open the table in datasheet view and experiment: How does MS Access respond if you try to create a new row with an existing primary key value?

Short answer

To set the Primary key, the deptCode field should be selected in Design View, then the Primary Key button should be clicked. Any rejections by MS Access likely indicate duplicates in the deptCode values, which should be amended in Datasheet View. Once the primary key is established, its functionality can be explored by attempting to create a new row with a pre-existing primary key value.

Step-by-step solution

Set the Primary Key

In the Department table's Design View, the deptCode field should be selected, followed by clicking on the Primary Key button. When done correctly, the deptCode field will display a key symbol next to it.

Handle Duplicates

If MS Access rejects the primary key, it suggests that there may be duplicated values in the deptCode fields. To remediate this, the table should be viewed in Datasheet View, where the duplicated value needs to be located and amended.

Testing the Primary Key

Once the primary key has been accepted by MS Access, the table should be opened in datasheet view. Experimentation involves trying to create a new record row using an already existing primary key value and observing MS Access's response.

Key concepts

Primary Key Designation

In Microsoft Access, setting a primary key is crucial for database integrity. The primary key uniquely identifies each record within a table and is the cornerstone for building relationships between tables. When designating a primary key, one must choose a field that contains unique values for each record. For instance, if you have a Department table, a natural choice for the primary key could be a department code field (deptCode), assuming each department has a distinct code.

To set a primary key, you'd go to the Design View of your table, select the appropriate field, and click on the Primary Key button. When set correctly, a key icon will appear next to the field name, indicating that the field is now the primary key. It's important to ensure that this field is not only unique but also non-nullable, meaning that it cannot contain empty values. This guarantees that every record can be uniquely identified.

Duplicate Value Handling

Duplicate values in a field designated for a primary key pose a challenge in Microsoft Access. Since a primary key's main role is to ensure each record's uniqueness in a table, duplicated entries are not allowed. If Access detects duplication upon attempting to set a field as a primary key, it will reject the designation.

To resolve this issue, it is necessary to eliminate any duplicates. This means switching to Datasheet View and reviewing the data in the primary key field. Identifying and modifying or removing any repeated entries is essential. When duplicates are corrected, and all values are unique, Access will permit setting the field as the primary key. Always remember that good database design includes planning for unique identifiers to avoid such issues from the outset.

Datasheet View Experimentation

The Datasheet View in MS Access offers a spreadsheet-like environment where data entry and editing is straightforward. After successfully designating a primary key, it’s useful to switch to Datasheet View and conduct some experimentation. The goal is to see firsthand how Access handles data integrity issues related to primary keys.

Try adding a new record with an existing primary key value. Access should display an error message, indicating that you cannot have duplicate values in the primary key field. This real-time experimentation facilitates a deeper understanding of primary key constraints and enforces the concept that primary keys must be unique for each record in a table.