Concepts

In general QueryCat is made up of three components:

  • Rows inputs are data providers that are equivalent to rows in a SQL table containing the data you want to process. There are built-in Rows Inputs (CSV, IIS W3C, others) but you can attach more using plugin DLLs.

  • SQL-Like Engine processes the rows generated by a Rows Input, using a dialect of the SQL language that includes common SQL clauses (WITH, SELECT, UNION, WHERE, GROUP BY, HAVING, ORDER BY), aggregate functions (SUM, COUNT, AVG, MAX, MIN), and a set of functions. The resulting records are then sent to an Rows Output.

  • Rows Output are generic consumers of records; they can be thought of as SQL tables that receive the results of the data processing. QueryCats's built-in outputs can be CSV file, system console and others.

Rows Input -> SQL backend -> Rows Output

Types

There are following column data types are supported:

Name Aliases Range Comment
INTEGER INT, INT8 -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
FLOAT REAL ±5.0 × 10−324 to ±1.7 × 10308 Precision is ~15-17 digits.
NUMERIC DECIMAL ±1.0 x 10-28 to ±7.9228 x 1028 Precision is 28-29 digits.
BOOLEAN BOOL true or false
TIMESTAMP Date and time values.
STRING TEXT Text data.
INTERVAL Time interval.
ARRAY List of variant values.
MAP Key-value dictionary.
BLOB Binary large object.
OBJECT
NULL Special type that represents "nothing" value.

  • For boolean true additional values can be used: 1, yes, on, t. Boolean false: 0, no, off, f.

  • Every column is considered to be nullable. If value is empty it will be parsed as NULL.

  • You can unescape string by preceding 'E' character (upper or lower case) before string. For example: E'Hello,\n\nHow are you?'.