Identifier-item file

An identifier-item file is a text file that lists transactions in identifier-item format. Each transaction has a unique identifier. Each line associates a transaction identifier with an item in that transaction.

Each line must contain at least two columns, one for the identifier and one for the item.

For identifier-item files, the Data Import Wizard:

Allows the user to specify whether the data is ordered by identifier. Ordered identifier-item files can be imported more efficiently than unordered files. An identifier-item file is ordered if all identifier-item pairs for an identifier appear as consecutive lines in the input file. For example, if the file is sorted by identifier then it is ordered.
Allows the user to select which columns contain the identifier and item. Other columns are ignored.
Allows the user to select the column delimiter. Any character may be used as a column delimiter.
Allows the user to sample from the data. The user can select the percentage of transactions to import. In this case a random selection of transactions is imported. Only these transactions are used in the analysis.

For example, the following shows the content of an identifier-item file containing two columns delimited by commas, the first column containing the identifier and the second the item. It is ordered by identifier.

001, apples
001, oranges
001, bananas
002, apples
002, carrots
002, lettuce
002, tomatoes

Transaction 001 contains apples, oranges and bananas. Transaction 002 contains apples, carrots, lettuce and tomatoes.

Another example, shows the content of an identifier-item file containing three columns delimited by colons, the first column containing the identifier, the second the item price, and the third the item.

001:51:oranges
002:66:lettuce
001:68:apples
002:85:tomatoes
002:95:carrots
001:105:bananas
002:220:apples

Transaction 001 contains apples, oranges and bananas. Transaction 002 contains apples, carrots, lettuce and tomatoes. To import this data select colon as the column delimiter, column 1 as the identifier column, and column 3 as the item column. The column containing item prices will be discarded by the data import process.

This second example is not ordered by identifier as the lines listing the items for each identifier are not consecutive.