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/* This file is part of the KDE project
Copyright (C) 2003 Lucijan Busch <[email protected]>
Copyright (C) 2004 Jaroslaw Staniek <[email protected]>
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; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifndef KEXIDBPARSER_H
#define KEXIDBPARSER_H
#include <tqobject.h>
#include <tqptrlist.h>
#include <tqvariant.h>
#include <kexidb/field.h>
#include <kexidb/expression.h>
namespace KexiDB
{
class Connection;
class QuerySchema;
class TableSchema;
class Field;
/**
* Provides detailed i18n'ed error description about the \a Parser .
*/
class KEXI_DB_EXPORT ParserError
{
public:
/**
* Empty constructor.
*/
ParserError();
/**
* Constructor.
*
* \param type The errortype.
* \param error A description of the error.
* \param hint Token where the error happend.
* \param at The position where the error happend.
*/
ParserError(const TQString &type, const TQString &error, const TQString &hint, int at);
/**
* Destructor.
*/
~ParserError();
/**
* \return the errortype.
*/
TQString type() { return m_type; }
/**
* \return a descriping error message.
*/
TQString error() { return m_error; }
/**
* \return position where the error happend.
*/
int at() { return m_at; }
private:
TQString m_type;
TQString m_error;
TQString m_hint;
int m_at;
// bool m_isNull;
};
class ParserPrivate;
/**
* Parser for SQL statements.
*
* The best and prefeerred way to run queries is using the KexiDB::Parser functionality
* and use the resulting QuerySchema object since this offers a database-backend-independent
* way to deal with SQL statements on the one hand and offers high level
* functionality on the other. Also BLOBs like images are handled that way.
*
* For example if we like to use the SELECT statement
* "SELECT dir.path, media.filename FROM dir, media WHERE dir.id=media.dirId AND media.id=%s"
* we are able to use the \a Connection::prepareStatement method which takes the type of
* the statement (in our case \a PreparedStatement::SelectStatement ), a list of fields (in
* our case dir.path and media.filename) and returns a \a PreparedStatement::Ptr instance.
* By using the \a QuerySchema::addRelationship and \a QuerySchema::addToWhereExpression methods
* the SQL statement could be extended with relationships and WHERE expressions.
*
* For more, see \a KexiDB::PreparedStatement and \a Connection::selectStatement() . A more
* complex example that looks at what the user has defined and carefully builds
* \a KexiDB::QuerySchema object, including the WHERE expression can be found in
* the Query Designer's source code in the method \a KexiQueryDesignerGuiEditor::buildSchema().
*/
class KEXI_DB_EXPORT Parser
{
public:
/**
* The operation-code of the statement.
*/
enum OPCode
{
OP_None = 0, /// No statement parsed or reseted.
OP_Error, /// Error while parsing.
OP_CreateTable, /// Create a table.
OP_AlterTable, /// Alter an existing table
OP_Select, /// Query-statement.
OP_Insert, /// Insert new content.
OP_Update, /// Update existing content.
OP_Delete /// Delete existing content.
};
/**
* constructs an empty object of the parser
* \param connection is used for things like wildcard resolution. If 0 parser works in "pure mode"
*/
Parser(Connection *connection);
~Parser();
/**
* clears previous results and runs the parser
*/
bool parse(const TQString &statement);
/**
* rests results
*/
void clear();
/**
* \return the resulting operation or OP_Error if failed
*/
OPCode operation() const;
/**
* \return the resulting operation as string.
*/
TQString operationString() const;
/**
* \return a pointer to a KexiDBTable on CREATE TABLE
* or 0 on any other operation or error. Returned object is owned by you.
* You can call this method only once every time after doing parse().
* Next time, the call will return 0.
*/
TableSchema *table();
/**
* \return a pointer to KexiDBSelect if 'SELECT ...' was called
* or 0 on any other operation or error. Returned object is owned by you.
* You can call this method only once every time after doing parse().
* Next time, the call will return 0.
*/
QuerySchema *query();
/**
* \return a pointer to the used database connection or 0 if not set
* You can call this method only once every time after doing parse().
* Next time, the call will return 0.
*/
Connection *db() const;
/**
* \return detailed information about last error.
* If no error occurred ParserError isNull()
*/
ParserError error() const;
/**
* \return the statement passed on the last \a parse method-call.
*/
TQString statement() const;
/**
* \internal
* sets the operation (only parser will need to call this)
*/
void setOperation(OPCode op);
/**
* \internal
* creates a new table (only parser will need to call this)
*/
void createTable(const char *t);
/**
* \internal
* sets \a query schema object (only parser will need to call this)
*/
//todo: other query types
void setQuerySchema(QuerySchema *query);
/**
* \internal
* \return query schema
*/
QuerySchema *select() const;
/**
* \internal
* INTERNAL use only: sets a error
*/
void setError(const ParserError &err);
/**
* \return true if the \param str is an reserved
* keyword (see tokens.cpp for a list of reserved
* keywords).
*/
bool isReservedKeyword(const char *str);
protected:
void init();
ParserError m_error; //!< detailed information about last error.
ParserPrivate *d; //!< \internal d-pointer class.
};
}
#endif
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