Data Files Created from Multiple Tables (OMS command)

When multiple tables are routed to the same data file, each table is added to the data file in a fashion similar to the ADD FILES command.

• Each subsequent table will always add cases to the data file.
• If column labels in the tables differ, each table may also add variables to the data file, with missing values for cases from other tables that don't have an identically labeled column.

Example

Multiple tables that contain the same column labels will typically produce the most immediately useful data files (data files that don't require additional manipulation).

• The second table contributes additional cases (rows) to the data file but no new variables because the column labels are exactly the same; so there are no large patches of missing data.
• Although the values for Command_ and Subtype_ are the same, the Label_ value identifies the source table for each group of cases because the two frequency tables have different titles.

Example

A new variable is created in the data file for each unique column label in the tables routed to the data file, which will result in blocks of missing values if the tables contain different column labels.

• The first table has columns labeled Beginning Salary and Current Salary, which are not present in the second table, resulting in missing values for those variables for cases from the second table.
• Conversely, the second table has columns labeled Education level and Months since hire, which are not present in the first table, resulting in missing values for those variables for cases from the first table.
• Mismatched variables, such as those in this example, can occur even with tables of the same subtype. In fact, in this example, both tables are of the same subtype.