Temporary and Permanent lists

Lists belong to one of two categories - temporary and permanent. Temporary lists do not exist when you restart IJC, while permanent lists persist across restarts. Permanent lists are saved to the database and continue to exist until you choose to delete them. Temporary lists can be made permanent. Both types can be renamed or deleted. To convert a temporary list to a permanent one:

• Right click on the list and choose 'Make permanent' or 'Make temporary'

• Drag the list from the temporary folder to the permanent folder (or vice-versa)
  When you execute a query a temporary list is automatically created for you. These lists are temporary as a large number of them might be generated. You can make any of these temporary lists permanent if you want to re-use it in later IJC sessions. You can also convert the IDs to those of a different field.

Lists and Fields

As we have seen, a temporary list is created as a result of running a query. Such a list corresponds to a list of the values from the ID field of the Entity. These IDs are the IDs of the row, which correspond to the primary key values in the database. This is the only type of field for which temporary lists can be created. However (since IJC 5.3.2), lists of values from fields other than the ID field can also be managed by IJC as permanent lists, and values of lists for one field can be converted to those for a different field. Ways of creating and editing lists are described later.

Lists for each field are displayed in a folder for each field. Only the ID field folder is shown by default. Other fields are only shown if there are any lists for the field.

List management is most useful for fields that have unique values, like the ID field of the entity. The value of the ID field uniquely identifies a row in the database table. Support for permanent lists for fields other than the ID field was added in IJC 5.3.2 primarily to manage the situation where there was an additional field that is a more meaningful identifier (e.g. the compound ID), However, the values in the field do not have to be unique, and in some cases this can be useful. For instance you can run a search to generate a list of IDs, then convert that list to a list of the molecular formula field to generate a list of all the formulae within that set of results. When that list is applied all structures with any of those formulae will be seen. It is important to realise that this sort of operation is not commutative. e.g. converting a list of Field1 to one for Field2 and then back again to Field1 will not result in the original IDs if the values of either field are not unique.

List management supports only integer and text fields. It is not thought likely that other types of fields will be useful. Also, not all text fields will be suitable for list management. It is designed only for values that are simple single line values. More complex multi-line or lengthy text strings will not be suitable.

Creating and editing lists

There are a number of ways of creating or editing lists:

Automatic creation when queries are executed

• A temporary list of the ID field is automatically created whenever a query is executed.

Manually entering the IDs

• You can edit a list by right clicking on it an choosing 'Edit list'. The list editor opens allowing you to manually specify the values. These can be typed in or pasted from the clipboard. The syntax is simple text with each value on a separate line.

  

Importing/exporting the values from a file

• A list can be created by importing from a file. The syntax is simple text with each value on a separate line. Similarly, values in a list can be exported to a file. Perform these operations by choosing 'Import list' or 'Export list' from the right click context menu of the list or by using the icon in the toolbar.

Converting the values from a different field

• Values for a list of one field can be converted to values for a different field. This is most commonly used to convert temporary lists generated when a query is executed to a list of values for a different field (e.g. your compound IDs) but can be used to convert between any field. To perform this either:
  Drag and drop the list to the folder for the required field
  or
  Right click context menu of the list and choose 'Convert list'. The convert list dialog will open:

  

Using list operations

You can perform operations on two or more lists at the same time. Select multiple lists and then open the drop-down shown below:

A list of operations is shown. They are as follows:

• Intersection

• Union

• XOR

• A and not B

• B and not A
  When you make a choice from the above operations, the following dialog is shown, with the corresponding operation selected:

You can apply the operation to an existing list (overwrite one of the input lists) or you can create a new list for the results. Use the "Save result to" area, at the bottom of the above dialog, for this purpose. List operations can only be used for lists of the same field (but remember that lists can be converted from one field to another). When using the ID field you can choose whether the new list is to be temporary or permanent.

Actions common to lists and queries

• Execute : Re-applies the list or query to the data tree, e.g. updates the results, in the main window to show the appropriate list or query.

• Share : control how the list or query is shared with other users (only present for permanent lists and queries).

• Make permanent/temporary : Converts between temporary and permanent lists. When you restart IJC only permanent lists will be present.

• Delete list or query : Delete the list or query.

• Rename : Assign a new name to the list or query.

• Properties : Show the properties of the list or query.

Operations specific to lists

• Add list to current result set : Add the IDs for that list to the current results.

• Remove list from current result set : Removes the IDs for that list to the current results.

• Edit list : Lets you edit the content of a list. The contents is just a list of IDs.

• Convert List : Convert the values of this list to those for a different field.

• Export list to file : Create a text file with the list IDs.

• Validate list : Removes any IDs for the lis that are not in the database.

Sharing lists and queries

If you are using a multi-user database then you can use lists and queries that other people have created. You can do this in one of two ways:

Sharing the list or query

One user can share a list or query with other users by changing the visibility of the item. This allows direct access to the other person's list or query, but does not let the second user change the first user's list or query. The second user will however see any subsequent changes that the first user makes (the details are loaded when the user first connects to the database). Details of sharing items are described in the document Sharing items with others .

Copying the list or query

To do this right click on the Permanent Lists or Permanent Queries node and select Copy list/query from other user. A dialog will open that allows you to specify the user and the list/query.

Note: This process creates a COPY of the list or query. Any changes the other user subsequently makes will not be reflected in your list/query. You would need to take a fresh copy.