include/Table.h

   1 /***************************************************************************
   2  *   Copyright (C) 2007 by www.databasecache.com                           *
   3  *   Contact: praba_tuty@databasecache.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   ***************************************************************************/
  16 #ifndef TABLE_H
  17 #define TABLE_H
  18 #include<ErrorType.h>
  19 #include<Util.h>
  20 class Predicate;
  21 class Condition;
  22 /**
  23 * @class Table
  24 *
  25 * @brief Handle to the database table.
  26 * Table is a set of data values organized using a model of horizontal rows and columns.<br>
  27 * Columns are identified by name and rows by values. It shall be visualized as a linked <br/>
  28 * list of related data<br/>
  29 * Functionality: <br/>
  30 *     1.insert <br/>
  31 *     2.update <br/>
  32 *     3.delete <br/>
  33 *     4.select with predicate or condition<br/>
  34 * <br/>
  35 *
  36 */
  37
  38 class FieldInfo;
  39 class Table
  40 {
  41     public:
  42     /** sets condition for the select, update and delete operations
  43     *   @param c condition
  44     */
  45     virtual void setCondition(Condition *c)=0;
  46
  47     /** binds application buffer to the specified field of the table.
  48     * Before doing any DML operations required fields are binded first.
  49     * Below are the candidates for this: <br/>
  50     * 1.All the fields in the projection list of select statement. <br/>
  51     * 2.Field list in the insert statement.<br/>
  52     * 3.Fields in the assignment list of update statement.<br/>
  53     * <br/>
  54     *   @param name field name in the table
  55     *   @param val  address of the application buffer. Memory should be allocated by
  56     *               the application before binding the buffer.
  57     */
  58
  59     virtual DbRetVal bindFld(const char *name, void *val)=0;
  60     /** marks the specified field to insert null when insert method is called.
  61     *   @param name field name in the table
  62     */
  63     virtual void *getBindFldAddr(const char *name)=0;
  64     virtual void markFldNull(const char *name)=0;
  65     /** marks the specified field to insert null when insert method is called.
  66     *   @param colpos field position
  67     */
  68     virtual void markFldNull(int colpos)=0;
  69
  70     /** clears the null mark which is set before.
  71     *   @param name field name
  72     */
  73     virtual void clearFldNull(const char *name)=0;
  74
  75     /** clears the null mark which is set before.
  76     *   @param colpos field position
  77     */
  78     virtual void clearFldNull(int colpos)=0;
  79
  80     /** checks whether the field value is null.
  81     *   @param name field name
  82     */
  83     virtual bool isFldNull(const char *name)=0;
  84
  85     /** checks whether the field value is null for the specified field position.
  86     *   @param colpos field position
  87     */
  88     virtual bool isFldNull(int colpos)=0;
  89 /*
  90     virtual void clearFldNull(const char *name)=0;
  91     virtual void clearFldNull(int colpos) =0;
  92 */
  93
  94     //DML operations
  95     /** executes the select statement. Based on the predicate(condition), respective index is
  96     * chosen for the select. Application should call execute before they start fetching
  97     * the values from the table.This starts scan on the table.
  98     * @returns DbRetVal
  99     */
 100     virtual DbRetVal execute()=0;
 101
 102     /** insert the tuple into the table. Prior to this, the binded buffer should be updated
 103     *  Values present in the binded buffers of all the fields are taken and stored in
 104     *  the table.<br/>
 105     * @returns DbRetVal
 106     */
 107     virtual DbRetVal insertTuple()=0;
 108
 109     /**update values in the current tuple of the table. It works only on top of select
 110     *  using fetch go to the tuple to be updated, then update the binded buffer value and
 111     *  then call this method to updates the field values in the tuple.
 112     * @returns DbRetVal
 113     */
 114     virtual DbRetVal updateTuple()=0;
 115
 116     /**deletes the current tuple of the table. It works only on top of select.
 117     *  using fetch first go to the tuple to be deleted, then call this method to delete.<br/>
 118     *  To delete all the tuples, do not set any condition and call fetch followed by delete
 119     *  in a loop till fetch exhausts.
 120     * @returns DbRetVal
 121     */
 122
 123     virtual DbRetVal deleteTuple()=0;
 124
 125
 126     /**deletes all the records which satisfies the condition set.
 127     * @returns int totalTuples deleted
 128     */
 129
 130     virtual int deleteWhere()=0;
 131
 132
 133
 134     /**deletes the all the records in the table. No transaction required to call this.
 135     *  It takes table level lock.
 136     * @returns DbRetVal
 137     */
 138
 139     virtual int truncate()=0;
 140
 141
 142
 143     //scan
 144
 145     /**fetches the next tuple in the table which satisfies the condition specified.
 146     * execute should be called before calling this method. Application buffer should be
 147     * binded to get the tuple values.
 148     * @returns void* NULL if there is no tuple.
 149     */
 150     virtual void* fetch()=0;
 151     virtual void* fetch(DbRetVal &rv)=0;
 152
 153     /**fetches the next tuple in the table which satisfies the condition specified.
 154     * execute should be called before calling this method. Application buffer need not be
 155     * binded to call this method.
 156     * @returns void* NULL if there is no tuple.
 157     */
 158     virtual void* fetchNoBind()=0;
 159     virtual void* fetchNoBind(DbRetVal &rv)=0;
 160
 161
 162     /**closes the scan. Needs to be called before calling execute again on the same table handle. It releases the resources
 163  acquired during the scan.
 164     * @returns DbRetVal
 165     */
 166
 167     virtual DbRetVal close()=0;
 168
 169     /**Retrieves the total space used for this table in bytes
 170     * @returns DbRetVal
 171     */
 172     virtual long spaceUsed()=0;
 173
 174     /**Retrieves the total number of tuples present in this table
 175     * @returns DbRetVal
 176     */
 177     virtual long numTuples()=0;
 178
 179     /**takes lock on the table
 180     * if bool shared flag is set, it will take shared lock, or else exclusive lock
 181     * @returns DbRetVal
 182     */
 183     virtual DbRetVal lock(bool shared)=0;
 184
 185     /**releases the lock acquired on the table
 186     * @returns DbRetVal
 187     */
 188     virtual DbRetVal unlock()=0;
 189
 190     /**sets the undo log flag. If this flag is unset then undo logs will not be generated
 191     * @returns DbRetVal
 192     */
 193     virtual DbRetVal setUndoLogging(bool flag)=0;
 194
 195     virtual DbRetVal getFieldInfo(const char *fieldName, FieldInfo *&info)=0;
 196     virtual List getFieldNameList()=0;
 197     virtual char* getName()=0;
 198     virtual void printSQLIndexString()=0;
 199
 200     virtual ~Table() { }
 201 };
 202 #endif