What Is a Slot?


A slit or narrow opening, esp. one for receiving something, as a coin or a letter. Also: a position in a group, series, or sequence; an assignment or job opening.

In sports, a slot is the area between the face-off circles on an ice hockey rink. The slot is a difficult position to defend, and it allows players more freedom to attack the puck without being smothered. A player in this position is often referred to as a “slot.”

The term slot is also used for a particular pattern of play, particularly in football. A good slot receiver is able to gain a lot of ground quickly, as well as make defenders miss on their tackles. The best slot receivers can easily gain 8-15 yards per catch, which is usually enough to break a big run into the open field.

There are several types of slots, each with a different column configuration. In general, a time-series slot holds data that repeats over a specified period of time. For example, a periodic slot may contain the pool elevations of a reservoir for each month of the year, or the monthly evaporation coefficients. A specialized time-series slot can hold text or numeric columns, and can handle irregular intervals as well.

Each slot has an associated “Slot Viewer,” which can be docked onto a model to display the slot’s data. The Slot Viewer is displayed with an icon/button in the slot’s column heading; clicking this button opens the slot in its own Slot Dialog. The dialog shows a list of the slot’s dates and data values, along with a set of icons and buttons that are used to configure the slot. These include controls to show/hide the slot’s data, show/hide its row labels, and configure its datetime display. The dialog also provides an option to “Compress Repeated Values,” which compresses the slots’ values into a single row.

Most series slots have a special display mode when they are configured to lookup or interpolate. The displayed data is the result of filtering the slot’s data by a given duration and then averaging the resulting sets of results over this duration. The resulting data is then displayed as a column of results for this duration.

In addition, a special type of periodical slot is available, which can be created from the Object menu, Add Series Slot with Periodic Input. These slots are similar to regular periodic slots, but they have an additional icon/button in the column heading, which opens the slot in its own dialog and allows the user to configure how its data is retrieved from the database. The dialog shown in Figure 6.10 demonstrates the key areas of a series slot, along with the various icon/button functions. A number of other configuration options are also available for these slots (see the Slot Dialogs documentation for more information). If a series slot has an expression, the expression is shown in the column heading, as illustrated below.