include/SqlStatement.h

   1 /***************************************************************************
   2  *   Copyright (C) 2007 by Prabakaran Thirumalai   *
   3  *   praba_tuty@yahoo.com   *
   4  *                                                                         *
   5  *   This program is free software; you can redistribute it and/or modify  *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation; either version 2 of the License, or     *
   8  *   (at your option) any later version.                                   *
   9  *                                                                         *
  10  *   This program is distributed in the hope that it will be useful,       *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15  *   You should have received a copy of the GNU General Public License     *
  16  *   along with this program; if not, write to the                         *
  17  *   Free Software Foundation, Inc.,                                       *
  18  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
  19  ***************************************************************************/
  20 #ifndef SQLSTATEMENT_H
  21 #define SQLSTATEMENT_H
  22 #include <SqlConnection.h>
  23 //#include "Statement.h"
  24 //#include<CSql.h>
  25 class Statement;
  26 class ParsedData;
  27
  28 /**
  29 * @class SqlStatement
  30 *
  31 * @brief Handle to the sql statement.
  32 * It is used to execute queries and return the values from the database<br>
  33 * Sql Statement is fed to the prepare method first and then it should be executed. <br/>
  34 * Functionality: <br/>
  35 *     1.Input values for insert statement <br/>
  36 *     2.Iterator for retrieving rows from the table <br/>
  37 *     3.Parameter support for performance.<br/>
  38 * <br/>
  39 * @author Prabakaran Thirumalai
  40 */
  41 class SqlStatement
  42 {
  43     public:
  44     /** Default constructor
  45     */
  46     SqlStatement();
  47     /** sets connection handle to be used for subsequent operations
  48     *   @param con SqlConnection*
  49     */
  50     void setConnection(SqlConnection *con);
  51
  52     /** compiles the sql statement. It calls the parser and tokenizes the statement
  53     * into logical plan. This method sets the statement string which needs to be executed.
  54     * free method needs to be called, if application wants to use the same handle to compile
  55     * another sql statement.
  56     * @param stmt sql statement string
  57     * @returns DbRetVal
  58     */
  59     DbRetVal prepare(char *stmt);
  60
  61     /** executes the sql statement. For insert, update, delete queries execute performs the
  62     * required operation on the table.
  63     * For Select queries, application should call execute before they start fetching
  64     * the values from the table.This starts scan on the table.
  65     * @param rowsAffect number of rows affected by the sql statement
  66     * @returns DbRetVal
  67     */
  68     DbRetVal execute(int &rowsAffect);
  69
  70     /**fetches the next tuple from the result of the execution of sql select query.
  71     * execute should be called before calling this method. Application buffer should be
  72     * binded to get the tuple values.
  73     * @returns void* NULL if there is no tuple.
  74     */
  75     void* fetch();
  76
  77     /** binds application buffer to the specified parameter position in the sql statement.
  78     * This method should be called for all the parameters in the sql statement.If not
  79     * execute will return error.
  80     * <br/>
  81     *   @param pos  position of the parameter in the statement
  82     *   @param val  address of the application buffer. Memory should be allocated by
  83     *               the application before binding the buffer.
  84     */
  85     DbRetVal bindParam(int pos, void*);
  86
  87     /** binds application buffer to the specified field position of the projection list
  88     *  in the select query. This method should be called only for select queries.
  89     * Before executing select queries, required fields must be binded first.
  90     * <br/>
  91     *   @param pos  position in the projection list
  92     *   @param val  address of the application buffer. Memory should be allocated by
  93     *               the application before binding the buffer.
  94     */
  95     DbRetVal bindField(int pos, void* val);
  96
  97     /**Fres all the resources held for the sql statement. Needs to be called before calling prepare again on the same statement handle.
  98     * @returns DbRetVal
  99     */
 100     DbRetVal free();
 101
 102     /**Retrieves the total number of projection fields in the statement
 103     * @returns int no of projection fields
 104     */
 105     int noOfProjFields();
 106
 107     /**Retrieves the total number of parameters in the statement
 108     * @returns int no of parameters
 109     */
 110     int noOfParamFields();
 111
 112     /**Retrieves the field info for the required projection field position in statement
 113     * @param projPos int - projection field position
 114     * @param info FieldInfo*& - OUT parameter
 115     * @returns DbRetVal
 116     */
 117     DbRetVal getProjFldInfo(int projPos, FieldInfo *&info);
 118
 119     /**Retrieves the field info for the required parameter position in statement
 120     * @param projPos int - parameter position
 121     * @param info FieldInfo*& - OUT parameter
 122     * @returns DbRetVal
 123     */
 124     DbRetVal getParamFldInfo(int paramPos, FieldInfo *&info);
 125
 126     private:
 127     SqlConnection *con;
 128     Statement *stmt;
 129     ParsedData pData;
 130 };
 131
 132 #endif