Author: vsssadmin

Here we will see the record editing techniques used to modify a table definition as well as the data introduced into it.

If we wishmake an alteration in the definition of an existing table (e.g to add, extend or delete an existing column etc…) we need to make a modification in its design.

Open the database where the table we want to modify is found if you are not already there.

Select the table that you want to modify by clicking on it so that its name stands out.

Click on the Design button in the database window.

The Table Design window studied in the previous unit will appear.

To modify a field design, position the cursor over the field to modify, and perform the necessary substitutions.

To add a new field,

go to the end of the table and type in the new field definition.

or,

situate yourself in an already existing field and click on the button in the Table Design bar, in this last case the new field will be inserted before the one in which we are positioned.

To delete a field,

position yourself in the field and click on the button in the Table Design bar.

or,

select the whole row corresponding the field by clicking on its extreme left, and when it stands out press the Del key.

The field, as well as the data stored in it will be erased from the table.

And lastly, save the table.

To practice these operations you can perform the Step by step Exercise Modifying the table design.

To introduce data into a table we can choose:

– In Database window, select the table to fill in by clicking on its name and click on the button to open the table.

– In Database window, double click on its name.

– If you are in Table design window, click on the Datasheet button in the Table design bar.

In all three cases the Datasheet window will appear:

Each rows allow us to introduce a record.

Write the value of the first field of the record.

Press ENTER to go to the next field in the record.

Once we have finished introducing all data in fields in the first record, we press ENTER key to introduce the data in the second record.

The moment we change to a different record, the record that we were in will be stored, and it is therefore not necessary to save the records again.

Click on the Close button in the Datasheet window to conclude this table.

If we want to delete an entire record:

Select the record to eliminate by clicking on the box on its extreme left (named record selector).

The record will remain selected.

Press the DEL key on the keyboard or on the button on the Datasheet bar.

Is we need to modify an inserted value all we need to do is situate ourselves over the value and re-tyte it.

If we need to alter something in the tables’ structure, we will need to go to Design view by clicking on the button on the Datasheet bar.

To practice these operations you can perform the Step by step Exercise Introduce data.

To move around the various records contained in a table we can use the Navigation buttons:

The bar indicates to us which record we are in and the total number of records in the table.

The current record is indicated in the white box.

In the final number where we see of 3, the total number of records is indicated to us.

By clicking on the different buttons we can perform the operations explained next:

to go to the first record in the table.

to go to the previous record in the table.

to go to the next record in the table.

to go to the last record in the table.

To create a new record that is automatically situated at the end of the table.

We can also go directly to a determined record in the following way:

Double clic in the white box where the current record number is situated.

Write the number of the record we want to go to.

Press ENTER.

We can also move around the different fields and records by pressing the ARROW UP, ARROW LEFT, ARROW DOWN, and ARROW RIGHT keys on the keyboard.

We will fill in the grid defining each of the columns that compose the table:

We can define a field using the field builder which allows us to define fields from those in sample tables and are activated clicking on the button on the toolbar. For more information on the Field builder clic here .

Or we can define our own fields as explained next.

In the first row write the name of the first field, and by pressing the ENTER key we move to Data Type column, which by defect will be Text. Should we choose to change the type of data, click on the arrow of the drop down list and select another type.

For more information on different data types clic here

If you require more information on the Lookup Wizard… clic here .

When we choose a type for the data, at the bottom of the window, the Field properties section is activated so as to be able to indicate more characteristics for the field, we will look at these characteristics in detail in the next unit.

Press ENTER next to go to the third column of the grid.

It is not necessary to use this column as it only serves to write comments; usually a description of the field for the person who will be introducing data so as to know what to write, this comment will appear on the status bar on the data page.

Repeat the process until all the fields (columns) in the table have been defined.

Before saving the table we need to assign a primary key.

The primary key provides a unique value for each row in the table and serves to identify the records in such a way that with this key we can be sure of not mistaking the record being identified. In a table we can not define more than one primary key, but we can have a multiple-field primary key (one primary key defined on several fields.

To assign a primary key to a field follow these instructions:

Click on the name of the field that will be the primary key.

Click on the Primary key button on the toolbar.

On the left of the field name will appear a key indicating to us that this field is the primary key of the table.

If we want to define a multiple-field primary key (based on various fields), hold down the Ctrl key and click on all those fields, then click on the button.

Important: Remember that a field or group of fields forming the primary key of a table cannot contain null values and neither have two rows in the table with the same value in the primary key fields.

When we try to insert a new row with values that infringe on these two rules the system will not allow us to create the row and will return an error.

To save a table we need to:

Go to the File menu and select Save.

Or click on the Save button on the toolbar.

As our table does still not have a name, the following dialogue box will appear:

Write the name of the table.

Click on the OK button.

Note: If we have not assigned a primary key before saving the table, a dialogue box will appear advising us of this, and asking whether we would like Access to create one like this:

If we decide Yes, it will create a Autonumber field and will define it as the primary key.

If we decide No, the table is saved without a primary key, a primary key is convenient but not obligatory.

To close a table, follow these steps:

Go to the File menu and select the Close option.

Or, clic in the Close button in the Database window.