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Figure 1. Table tab

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TQL TQL

Table Query Language

The Table Query Language (TQL "tickle" [tik-uh l]) is an interpreted language used as part of

Results Manager Table tab to highlight / filter columns based on user specified criteria.  Queries are entered by the user into the search bar at the top of the columns and the results are highlighted within the table columns (Figure 2).  An optional filtering check-box can also be selected which will ensure that only rows containing matches are displayed.   Successful queries (meaning those that have resulted in cell matches result in the query string)  are displayed in green, while unsuccessful queries are displayed in red.

Figure 2. Table tab, TQL search example. 

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Supported Features

TQL can be used to search for the following information:

• Arbitrary

• strings - these attempt to match the characters typed in to any raw content shown in any of the cells.  e.g., "01/07" will match any year's date "01/07/2001", "01/07/2002"
• Date Range - only a block of dates can be specified.  e.g., "01/07/2001 > && < 01/07/2002"
• Any Field Value - numeric logic applied to all cells e.g., "> 10 && < 20"
• Specific Column Value - like the any field match but specific to particular columns e.g., "$1 > 10 && $2 < 20"
• Cross Column Comparisons - look for relationships between columns e.g., "$1 > $2"

Language Structure

There are two main search types:

1. String - these searches attempt to find the entered substring in any table cell.  No logical expressions can apply to these searches as they have no contextual information.
2. Expression - these searches determine the actual value of the cell in the appropriate format and allow for logical relationships

Which are based around four main types of cell information

1. Dates (Expression) - e.g., "01/07/2001"
2. Numerics (Expression) - e.g., "155.51"
3. Column Specifications (Expression) - e.g., "$1"
4. Arbitrary Strings (String) - e.g.,  "12/1", "12."

When a search is entered into the table, the parser will attempt to always match an an Expression search search.  In cases where this fails it will revert back to a a String search search.  Both  Both String and  and Expression searches  searches can be combined but no equality can be used to qualify the String portion

For example, if the user entered  "12/1" it would be a a String search  search as there is not enough text entered to form a full date. This would result in it scanning through all cells and matching any in the Date column which contain the exact substring.   Entries such as: "12/10/2005" and "05/12/1001" would be highlighted.  However, if a full valid date is entered such as "12/10/2005" then this would be an an Expression search  search and only the "12/10/2005" would be matched.  The downside of of String searches  searches is that they no not allow for any logic expressions as there is no context to the match.  So the user can't look for later dates based on the "> 12/1" String search search, where-as the Expression search the Expression search "> 12/10/2005" will.

Equality operations

The

equality operations

supported are shown in Table 1. It can be noted that the not equal and equal operators have two versions which can be used.  This is for flexibility and both versions operate in an identical manner.

Table 1. Table Query Language, Comparison operators

Logical / Boolean operations

The following boolean / logical operations are supported:

• "&" or "&&" -

• logical AND
• "|" or "||" -

• logical OR

As with the equality operators, boolean AND and OR have two versions which can be entered but each operate identically.  They evaluate each side of the expression and then combine the results as specified using boolean logic.

• AND is true when both sides of expression are true
• OR is true when either or both sides of the expression are true

TQL does not currently support any

other logical connectives such as XOR.

Column Notation

When wanting to specify a particular column, the user can enter the column number (starting at 0) preceded by the dollar symbol ("$").  So to specify the Date column the user would enter "$0" whereas to specify the first value column they would enter "$1".  At evaluation time the parser will replace the column specified with the particular cell value and then evaluate.  This is useful for looking for relationships amongst two different time-series.

Figure 3. TQL, column notation.

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Date Format

TQL can use dates as a value for evaluation.  It does this by converting the Date value into the machine's current Date culture.  This means that user should be aware of if they are using "dd/mm/yyyy" or  or "mm/dd/yyyy" format  format specifiers as part of their general operating system set-up.  Dates can only be used to compare and perform logical comparisons to other Dates within the first column ("$0")

TQL Examples

The following examples in Table 2 show typical usage, all date usages assume a culture format "dd/mm/yyyy".  For clarity, queries that are interpreted as a a String search  search are indicated with an an (S) while  while Expression searches  searches are marked with an an (E).

Table 2. TQL Examples

Appendix

- Language Definition

TQL is a a context-free grammar which ignores ignores white-space.  The  The Extended Backus-Naur Form metasyntax for TQL is as follows:

EBNF

   Statement := String | Expression, { Logical Expression };
  Expression := [Value] Logical Value;
       Value := Number | Date | Column;
      String := Digit | Point | Slash { Digit | Point | Slash };
     Logical := "&&" | "&" | "|" | "||";
    Equality := "<" | "<=" | ">" | ">=" | "!=" | "!" | "==" | "=";
      Column := "$", Natural;
        Date := Digit [, Digit], Slash, Digit [, Digit], Slash, Digit, Digit, Digit, Digit;
     Natural := Digit {Digit};
     Integer := ["-"], Natural;
       Point := ".";
       Slash := "/";
       Digit := "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9";
      Number := Integer, [Point, Digit {Digit}];