include/Session.h

   1 /***************************************************************************
   2  *                                                                         *
   3  *    Copyright (C) Lakshya Solutions Ltd. All rights reserved.            *
   4  *                                                                         *
   5  ***************************************************************************/
   6
   7 #ifndef SESSION_H
   8 #define SESSION_H
   9 #include<os.h>
  10 #include<ErrorType.h>
  11 class DatabaseManager;
  12 class UserManager;
  13 class Session;
  14 /**
  15 * @enum IsolationLevel
  16 * @brief Represents isolation level of the transaction.
  17 */
  18 enum IsolationLevel
  19 {
  20     READ_UNCOMMITTED = 1,
  21     READ_COMMITTED = 2,
  22     READ_REPEATABLE = 3,
  23     WRITE_OSYNC = 4 //this will work only from sqlapi
  24                     //for dbapi WRITE_OSYNC = READ_REPEATABLE
  25 };
  26
  27 /**
  28 * @class Connection
  29 *
  30 * @brief Represents a database connection.
  31 * All database operations shall be done within the context of the connection. <br>
  32 * Application should first create object of this class for accessing the database.<br/>
  33 * Each connection has only one active transaction at any given point of time, all <br/>
  34 * operations which happen using this connection object will be done as part of that <br/>
  35 * transaction.<br/>
  36 * <br/>
  37 * Functionality: <br/>
  38 *     1.Connection Management (connect and disconnect) <br/>
  39 *     2.Transaction Management (start, commit, abort) <br/>
  40 *     3.Provides getter methods for database manager and user manager <br/>
  41 *     4.Isolation Level support. REPEATABLE READ, <br/>
  42 *       READ COMMITTED and READ UNCOMMITTED isolation levels<br/>
  43 * <br/>
  44 *  Note: <br/>
  45 *  SERIALIZABLE isolation level is not supported.
  46 *
  47 */
  48
  49 class DllExport Connection
  50 {
  51     Session *session;
  52     public:
  53     Connection() { session = NULL; }
  54     ~Connection();
  55
  56     /** opens connection to the database
  57     *   @param username username for authentication
  58     *   @param password password for authentication
  59     *   @return DbRetVal
  60     */
  61     DbRetVal open(const char*username, const char*password);
  62
  63
  64     /** closes connection to the database and releases all the resources
  65     *   @return DbRetVal
  66     */
  67     DbRetVal close();
  68
  69     /** gets the database manager object.
  70     *   @return DatabaseManager
  71     */
  72     DatabaseManager* getDatabaseManager();
  73
  74     /** gets the user manager object.
  75     *   @return UserManager
  76     */
  77     UserManager* getUserManager();
  78
  79     /** Starts a transaction.
  80     *   The previous transaction should be either committed or rollback <br/>
  81     *   before startTransaction is called. <br/>
  82     *   Application are required to start transaction before they attempt any <br>
  83     *   database operation.
  84     *   @return DbRetVal
  85     */
  86     DbRetVal startTransaction(IsolationLevel level = READ_COMMITTED);
  87
  88     /** Commits active transaction.
  89     *   It makes all the changes made in the current transaction permanent and <br/>
  90     *   it also releases the locks held by the current transaction.<br/>
  91     *   After a transaction commits, application is required to start another <br/>
  92     *   transaction for further database operations.
  93     *   @return DbRetVal
  94     */
  95     DbRetVal commit();
  96
  97     /** Aborts the active transaction.
  98     *   undo all the changes made in the current transaction and it also <br/>
  99     *   releases the locks held by the current transaction.<br/>
 100     *   After a transaction rollback, application is required to start another <br/>
 101     *   transaction for further database operations.
 102     *   @return DbRetVal
 103     */
 104     DbRetVal rollback();
 105
 106     DbRetVal getExclusiveLock();
 107     char *getUserName();// { return session->getUserName(); }
 108 };
 109
 110
 111 class DllExport Session
 112 {
 113     public:
 114     virtual DbRetVal open(const char*username, const char*password)=0;
 115     virtual DbRetVal close()=0;
 116
 117     virtual DatabaseManager* getDatabaseManager()=0;
 118     virtual UserManager* getUserManager()=0;
 119
 120     virtual DbRetVal startTransaction(IsolationLevel level)=0;
 121     virtual DbRetVal commit()=0;
 122     virtual DbRetVal rollback()=0;
 123     virtual DbRetVal getExclusiveLock()=0;
 124     virtual char * getUserName()=0;
 125     //TODO:: virtual int setAutoCommit(bool flag)=0;
 126     //TODO::support for save points
 127     virtual ~Session() { }
 128
 129 };
 130
 131
 132
 133 #endif