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 #include<DataType.h>
  21 class Predicate;
  22 class Condition;
  23 #ifndef SCANTYPE
  24 enum ScanType
  25 {
  26     fullTableScan = 0,
  27     hashIndexScan,
  28     treeIndexScan,
  29     unknownScan
  30 };
  31 #define SCANTYPE
  32 #endif
  33 /**
  34 * @class Table
  35 *
  36 * @brief Handle to the database table.
  37 * Table is a set of data values organized using a model of horizontal rows and columns.<br>
  38 * Columns are identified by name and rows by values. It shall be visualized as a linked <br/>
  39 * list of related data<br/>
  40 * Functionality: <br/>
  41 *     1.insert <br/>
  42 *     2.update <br/>
  43 *     3.delete <br/>
  44 *     4.select with predicate or condition<br/>
  45 * <br/>
  46 *
  47 */
  48
  49 class FieldInfo;
  50 class Table
  51 {
  52     public:
  53     /** sets condition for the select, update and delete operations
  54     *   @param c condition
  55     */
  56     virtual void setCondition(Condition *c)=0;
  57
  58     /** binds application buffer to the specified field of the table.
  59     * Before doing any DML operations required fields are binded first.
  60     * Below are the candidates for this: <br/>
  61     * 1.All the fields in the projection list of select statement. <br/>
  62     * 2.Field list in the insert statement.<br/>
  63     * 3.Fields in the assignment list of update statement.<br/>
  64     * <br/>
  65     *   @param name field name in the table
  66     *   @param val  address of the application buffer. Memory should be allocated by
  67     *               the application before binding the buffer.
  68     */
  69
  70     virtual DbRetVal bindFld(const char *name, void *val)=0;
  71     /** marks the specified field to insert null when insert method is called.
  72     *   @param name field name in the table
  73     */
  74     virtual void *getBindFldAddr(const char *name)=0;
  75     virtual DbRetVal markFldNull(const char *name)=0;
  76     /** marks the specified field to insert null when insert method is called.
  77     *   @param colpos field position
  78     */
  79     virtual DbRetVal markFldNull(int colpos)=0;
  80
  81     /** clears the null mark which is set before.
  82     *   @param name field name
  83     */
  84     virtual void clearFldNull(const char *name)=0;
  85
  86     /** clears the null mark which is set before.
  87     *   @param colpos field position
  88     */
  89     virtual void clearFldNull(int colpos)=0;
  90
  91     /** checks whether the field value is null.
  92     *   @param name field name
  93     */
  94     virtual bool isFldNull(const char *name)=0;
  95
  96     /** checks whether the field value is null for the specified field position.
  97     *   @param colpos field position
  98     */
  99     virtual bool isFldNull(int colpos)=0;
 100 /*
 101     virtual void clearFldNull(const char *name)=0;
 102     virtual void clearFldNull(int colpos) =0;
 103 */
 104
 105     //DML operations
 106     /** executes the select statement. Based on the predicate(condition), respective index is
 107     * chosen for the select. Application should call execute before they start fetching
 108     * the values from the table.This starts scan on the table.
 109     * @returns DbRetVal
 110     */
 111     virtual DbRetVal execute()=0;
 112
 113     /** insert the tuple into the table. Prior to this, the binded buffer should be updated
 114     *  Values present in the binded buffers of all the fields are taken and stored in
 115     *  the table.<br/>
 116     * @returns DbRetVal
 117     */
 118     virtual DbRetVal insertTuple()=0;
 119
 120     /**update values in the current tuple of the table. It works only on top of select
 121     *  using fetch go to the tuple to be updated, then update the binded buffer value and
 122     *  then call this method to updates the field values in the tuple.
 123     * @returns DbRetVal
 124     */
 125     virtual DbRetVal updateTuple()=0;
 126
 127     /**deletes the current tuple of the table. It works only on top of select.
 128     *  using fetch first go to the tuple to be deleted, then call this method to delete.<br/>
 129     *  To delete all the tuples, do not set any condition and call fetch followed by delete
 130     *  in a loop till fetch exhausts.
 131     * @returns DbRetVal
 132     */
 133
 134     virtual DbRetVal deleteTuple()=0;
 135
 136
 137     /**deletes all the records which satisfies the condition set.
 138     * @returns int totalTuples deleted
 139     */
 140
 141     virtual int deleteWhere()=0;
 142
 143
 144
 145     /**deletes the all the records in the table. No transaction required to call this.
 146     *  It takes table level lock.
 147     * @returns DbRetVal
 148     */
 149
 150     virtual int truncate()=0;
 151
 152     //scan
 153
 154     /**fetches the next tuple in the table which satisfies the condition specified.
 155     * execute should be called before calling this method. Application buffer should be
 156     * binded to get the tuple values.
 157     * @returns void* NULL if there is no tuple.
 158     */
 159     virtual void* fetch()=0;
 160     virtual void* fetch(DbRetVal &rv)=0;
 161
 162     /**fetches the next tuple in the table which satisfies the condition specified.
 163     * execute should be called before calling this method. Application buffer need not be
 164     * binded to call this method.
 165     * @returns void* NULL if there is no tuple.
 166     */
 167     virtual void* fetchNoBind()=0;
 168     virtual void* fetchNoBind(DbRetVal &rv)=0;
 169
 170
 171     /**closes the scan. Needs to be called before calling execute again on the same table handle. It releases the resources
 172  acquired during the scan.
 173     * @returns DbRetVal
 174     */
 175
 176     virtual DbRetVal close()=0;
 177     virtual DbRetVal closeScan()=0;
 178
 179     /**Retrieves the total space used for this table in bytes
 180     * @returns DbRetVal
 181     */
 182     virtual long spaceUsed()=0;
 183
 184     /**Retrieves the total number of tuples present in this table
 185     * @returns DbRetVal
 186     */
 187     virtual long numTuples()=0;
 188
 189     /**takes lock on the table
 190     * if bool shared flag is set, it will take shared lock, or else exclusive lock
 191     * @returns DbRetVal
 192     */
 193     virtual DbRetVal lock(bool shared)=0;
 194
 195     /**releases the lock acquired on the table
 196     * @returns DbRetVal
 197     */
 198     virtual DbRetVal unlock()=0;
 199
 200     /**sets the undo log flag. If this flag is unset then undo logs will not be generated
 201     * @returns DbRetVal
 202     */
 203     virtual DbRetVal setUndoLogging(bool flag)=0;
 204
 205     virtual DbRetVal getFieldInfo(const char *fieldName, FieldInfo *&info)=0;
 206     virtual List getFieldNameList()=0;
 207     virtual char* getName()=0;
 208     virtual char* getAliasName()=0;
 209     virtual void printSQLIndexString(FILE *fp=NULL, int fd=-1)=0;
 210     virtual void printSQLForeignString()=0;
 211     virtual DbRetVal compact()=0;
 212     //optimizer
 213     virtual DbRetVal optimize()=0;
 214     virtual ScanType getScanType()=0;
 215     virtual bool hasIndex(char *name)=0;
 216     virtual bool isTableInvolved(char *tblName)=0;
 217     virtual bool pushPredicate(Predicate *pred)=0;
 218     virtual void setPredicate(Predicate *pred)=0;
 219     virtual void printPlan(int space)=0;
 220     virtual void addPredicate(char *fname, ComparisionOp op, void *buf)
 221                  { return; }
 222     virtual bool isFKTable()=0;
 223     virtual void resetNullinfo()=0;
 224     virtual int getFldPos(char *name)=0;
 225     virtual ~Table() { }
 226
 227     virtual void setLoading(bool flag){};
 228
 229     //non virtual functions
 230     static void getFieldNameAlone(char *fname, char *name);
 231     static void getTableNameAlone(char *fname, char *name);
 232 };
 233
 234 #endif