Browsing

There are two ways to open a CASA table: on the command-line or through a file chooser dialog.

• Command-line: See Usage.
  
• File Chooser: Once a CasaBrowser window has been opened, files can be opened by selecting the File - Open Table menu option or by using the Ctrl+O keyboard shortcut.
  

If opening the table succeeded, the table should appear in a new tab. If opening failed, an error message will appear with details on the failure.
 
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To open a table with TaQL (see links for documentation), use the File - Open TaQL (Ctrl+Shift+O) command. You will be presented with a dialog to enter your TaQL command. There is a rudimentary TaQL command builder, but currently it is somewhat primitive and only supports the SELECT command. If using the builder, be sure to click the "Generate" button to generate the TaQL command before clicking "Accept".


 
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There are three ways to close a table: File - Close Table (Ctrl+W), which closes the currently selected table; File - Close..., which allows you to choose which of the opened tables you wish to close; and File - Close All, which closes all opened tables.

 
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When you close a CasaBrowser window, the default behavior is to save the currently opened "view." A view consists of:

• The last directory you opened a table from,
• A list of currently opened tables,
• Which table was currently selected.
• For each opened table:
  • Which columns (if any) were hidden,
  • Where each column was moved to (if they were moved),
  • Which rows were loaded,
  • The current row filter, if there was one,
  • The field formats, if there were any,
  • The current sort order (if any) of the fields.

If you do not wish the view to be saved, this may be turned off in the Options (see Browsing:Edit Options).
 
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Options for the CasaBrowser can be edited with the Edit - Options command. Currently, two options may be adjusted:

• Save View on Close: indicates whether, when the CasaBrowser is closed, the current view should be saved. (See Browsing:Saved Views).
• Debug Threshold: affects how much debugging output is printed to the console. Messages that have a debug level that is greater than or equal to the threshold are printed. For example, if the threshold is set to High, then only messages with a High level are printed, whereas a threshold of Medium will print High and Medium messages.

 
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Information about an opened table can be viewed by using the View - Table Information (Ctrl+I) menu command. A table information panel will open on the right side of the currently selected table. Information about tables provided include:

• Location on disk
• Total number of rows
• Whether the table allows for insertion and/or deletion of rows
• List and description of fields:
  • Field name
  • Field type
  • Field unit (if given)
  • Field UCD (if given)
  • Field ref (if given)
  • Field precision (if given)
  • Field width (if given)

The side panel can be closed with the "Close" button.

 
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Each opened table has three tabs associated with it; the first and topmost of these tabs is the data tab. The data tab has two primary components: the data table and page navigation.

• Data Table: a spreadsheet-like interface for viewing table data. The column headers consist of the table fields, and the row headers indicate which rows of the table are currently being viewed.
  
  Clicking on a cell will highlight the cell, its row, and its column. Double-clicking on a cell, for most data types, will enter into editing mode (see Editing); some data types, however, have special behavior for double-clicking:
  • Arrays: Text displayed in the data cell for an array will either be a (potentially abbreviated) view of the array itself in the case of a one-dimensional array, or the shape of the array. In either case, double-clicking will open an array viewer in a side panel on the right of the data tab. The rows and columns in the array viewer table correspond to the rows and column in the underlying array. In the case of an array having dimension greater than two, a two-dimensional "slice" of the array can be viewed at any given time.
    
  • Tables: Double-clicking on a table will follow the reference to that table and open it in a separate tab (if the table exists).
  
  
• Page Navigation: only a set number of rows are loaded from the table at one time. Thus, conceptually, the table can be seen as being separated into "pages", each page containing the number of loaded rows. At the bottom of the data tab are components that allow for page navigation and control.
  

 
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Each opened table has three tabs associated with it; the second and middle of these tabs is the table keywords tab. Each table keyword is displayed in a table in this component. Table keywords consist of the keyword name, the keyword type, and the keyword value.

One of the most common uses of the table keywords are to show the table's subtables. For these subtable keywords, the number of rows are also shown. Additionally, double-clicking on any subtable keyword will open the specified table in a new tab.
 
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Each opened table has three tabs associated with it; the third and bottommost of these tabs is the field keywords tab. Each field keyword is displayed in a tree in this component. Field keywords consist of the keyword name, the keyword type, and the keyword value.
 
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Any data item that has an integer type can be used as a row reference into a subtable. Right-clicking on a suitable data item will bring up a context menu that will allow you to follow the reference to any subtable defined in the table keywords. If the subtable is not currently open, it will be opened; if the subtable is open, its tab will be selected. The open table will then scroll to and highlight the row referenced by the data item.

 
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To view field options and information, right-click on a column header. A context menu will be presented with the following options:

• Field Information: Displays a pop-up dialog with the field name and type along with any field keywords.
• Statistics: For numerical fields, statistical information can be displayed. This includes the minimum, maximum, and mean. NOTE: the statistics are only for the rows currently loaded in the browser.
• Format Field: see Format Data Display.
• Hide Column: see Show/Hide Columns.

 
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The ability to filter rows based on data content is available through the View - Filter on Fields (Ctrl+Shift+F) menu command. (Note: Rows are filtered just on the display, not on the underlying table!) A filter consists of a set of rules; each rule is a logical statement involving the values of one table field. Multiple rules are logically "and"ed together to form the filter.

For example, suppose that all rows in which the VALID column is not 1 should be filtered out. To do this, enter the rule: VALID is equal to 1 and then run the filter. All rows that do not pass the filter rules are hidden in the view. If the page is changed, the filter is applied to the newly loaded rows.

The current filter can be cleared with the View - Clear Filter (Ctrl+Shift+C) menu command.

 
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Rows can be searched for by using the Edit - Find (Ctrl+F) menu command. A search is based on a set of rules; each rule is a logical statement involving the values of one table field. Multiple rules are logically "and"ed together to form the search.

For example, suppose that you want to search for rows in which the VALID column is equal to 1. To do this, enter the rule: VALID is equal to 1 and then run the search.

The first rule to match the search rule is highlighted in the data tab. Running search again will open a new rule dialog. To find the next row that matches the search rule, use Edit - Find Next (F3), or to find the previous row that matches the search rule, use Edit - Find Previous (Shift+F3).
 
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There are two ways to sort rows by their field values. The first is to click the field header in the data view, which will alternate between sorting on that row in ascending and descending order. The header will have an arrow indicating the sort order.


The second way is to use the Tools - Sort (Ctrl+S) command. A dialog will appear that will allow you to sort on multiple fields simultaneously. The sort is performed starting with the top field and ending with the bottom field. The header of the first field will have an arrow indicating the sort order.



Note that sorting only sorts on the currently displayed items, not the entire table.

To clear the current sort, use the Clear Sort button at the bottom of the data display.
 
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Displayed data can be formatted according to its type. To format data, use the View - Format Display... command and then choose the field to format. Depending on the type, different formatting options may be displayed. Once a desired format has been configured, it can be applied with the Set Format button.


Once a format has been set, it can be cleared by once again invoking the View - Format Display... command and then clicking the Clear Format button.
 
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Any column can be shown or hidden in both the data and the keywords tab. Columns can be shown or hidden in the View - Columns menu, or by right-clicking on the column header.

 
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Any column in the data table can be moved to an arbitrary location in the table view. Note: this does not change the order of the columns in underlying table on disk; it is merely a display change. To restore the columns to their original order, click the "Restore Columns" button.
 
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