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TaQL.h
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//# TaQL.h: The TaQL module - Casacore data querying
//# Copyright (C) 1994-2010
//# Associated Universities, Inc. Washington DC, USA.
//#
//# This library is free software; you can redistribute it and/or modify it
//# under the terms of the GNU Library General Public License as published by
//# the Free Software Foundation; either version 2 of the License, or (at your
//# option) any later version.
//#
//# This library is distributed in the hope that it will be useful, but WITHOUT
//# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
//# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
//# License for more details.
//#
//# You should have received a copy of the GNU Library General Public License
//# along with this library; if not, write to the Free Software Foundation,
//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
//#
//# Correspondence concerning AIPS++ should be addressed as follows:
//# Internet email: casa-feedback@nrao.edu.
//# Postal address: AIPS++ Project Office
//# National Radio Astronomy Observatory
//# 520 Edgemont Road
//# Charlottesville, VA 22903-2475 USA
#ifndef TABLES_TAQL_H
#define TABLES_TAQL_H
//# Includes
//# table expressions (for selection of rows)
#include <casacore/casa/aips.h>
#include <casacore/tables/TaQL/ExprNode.h>
#include <casacore/tables/TaQL/ExprNodeSet.h>
#include <casacore/tables/TaQL/TableParse.h>
namespace casacore { //# NAMESPACE CASACORE - BEGIN
// <module>
// <summary>
// TaQL is the query language for Casacore tables
// </summary>
// <use visibility=export>
// <reviewed reviewer="jhorstko" date="1994/08/30" tests="" demos="">
// </reviewed>
// <prerequisite>
// <li> <linkto module="Tables:description">Tables</linkto> module
// </prerequisite>
// <etymology>
// "TaQL" is the Table Query Language. Its pronounciation rhymes with bagel.
// </etymology>
// <synopsis>
// TaQL is an SQL-like language to query a Casacore table.
// Amongst its options are row select, sort, update, and delete.
// <br>Some more information is given in the description of the
// <linkto module="Tables:select and sort">Tables module</linkto>.
// A detailed description is given in <A HREF="../notes/199.html">note 199</A>.
//
// The high-level interface is using a TaQL command as described in
// <A HREF="../notes/199.html">note 199</A>. Such a command can be given
// in C++ (using TableParse.h), Python or the shell program 'taql'.
// The code for parsing and executing TaQL commands is quite complex.
// Processing a command consists of two steps.
// <ol>
// <li>
// First a command is parsed using 'flex' and 'bison'. The file TableGram.ll
// is used by 'flex' to recognize the tokens in the command. The file
// TableGram.yy defines the grammar which is used by bison to invoke
// actions on the recognized parts of the command. These actions
// consist of building a parse tree by means of class TaQLNode and
// associated classes. In this way the command is syntactically checked.
// <li>
// If the parsing is done successfully, the command is executed
// by walking through the parse tree using class TaQLNodeHandler.
// In its turn that class invokes functions in class TableParseQuery
// to check (semantically) and execute commands such as SELECT, UPDATE, etc..
// Note that subqueries are executed before the entire parse tree has
// been walked through, thus before possible later semantic errors are
// detected.
// <br>Expressions in the parse tree are converted to expression trees
// using the various TableExprNode classes. Expression trees are evaluated
// for each row in a table. Note that expressions can be used in many
// parts of a TaQL command.
// Functions in a command are handled by TableParseFunc.
// </ol>
//
// Expression trees can also be generated directly in C++ using class
// TableExprNode which is overloaded for many operators and functions
// (such as sin, max, etc.). In fact, TaQLNodeHandler uses this code.
// For example:
// <example>
// <srcblock>
// Table tab("my.ms");
// Table selection (tab(tab.col("ANTENNA1") == tab.col("ANTENNA2") &&
// tab.col("SPECTRAL_WINDOW_ID") == 0));
// </srcblock>
// creates a (reference) table containing the autocorrelations of the
// first spectral window in "my.ms".
// </example>
// </synopsis>
// </module>
} //# NAMESPACE CASACORE - END
#endif
casacore
this file contains all the compiler specific defines
Definition mainpage.dox:28