Defining fields in table layouts

In an Analytics table layout, a field is a single unit of data, such as employee ID, that together with other units of data form a record.

You can define two types of fields in Analytics table layouts:

• Physical fields
• Computed fields

All fields in Analytics must be assigned a data type (Character, Numeric, Datetime, or Logical) that determines how the values in the physical or computed fields are displayed and processed.

Physical fields

A physical field corresponds to actual data physically present in a data source, such as a file or a database. For example, a physical field named Amount could contain sales amounts, such as $88.50, $123.00, and so on.

In a table layout, a record specifies where data is located in the data source, and a physical field specifies the location of field data in the record.

Before you can open an Analytics table, the table layout must have at least one physical field defined. Typically, the physical fields in a table layout are automatically defined by Analytics when you define and import data using the Data Definition Wizard or the Data Access window. You can also manually define physical fields, if necessary, in the Table Layout dialog box.

For more information, see Defining physical fields.

Computed fields

A computed field is a "virtual field", created using an Analytics expression, that allows you to compute or calculate values that are not physically present in the data source. For example, you could create a computed field named Total Amount that uses the expression Amount * 1.05 to calculate total amounts including a 5% sales tax.

Amount field (physical)	Analytics expression	Total Amount field (computed)
$88.50	Amount * 1.05	$92.93
$123.00	Amount * 1.05	$129.15

Although computed fields do not correspond directly to physical data, they often reference one or more physical fields, such as the Amount field in the example above. Computed field expressions may also reference other computed fields, or they may contain functions that do not require fields as input parameters.

You define computed fields in the Table Layout dialog box.

For more information, see Defining computed fields.