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 DllExport 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,
  71                                                      bool isNullExpl=false)=0;
  72     /** marks the specified field to insert null when insert method is called.
  73     *   @param name field name in the table
  74     */
  75     virtual void *getBindFldAddr(const char *name)=0;
  76     virtual DbRetVal markFldNull(const char *name)=0;
  77     /** marks the specified field to insert null when insert method is called.
  78     *   @param colpos field position
  79     */
  80     virtual DbRetVal markFldNull(int colpos)=0;
  81
  82     /** clears the null mark which is set before.
  83     *   @param name field name
  84     */
  85     virtual void clearFldNull(const char *name)=0;
  86
  87     /** clears the null mark which is set before.
  88     *   @param colpos field position
  89     */
  90     virtual void clearFldNull(int colpos)=0;
  91
  92     /** checks whether the field value is null.
  93     *   @param name field name
  94     */
  95     virtual bool isFldNull(const char *name)=0;
  96
  97     /** checks whether the field value is null for the specified field position.
  98     *   @param colpos field position
  99     */
 100     virtual bool isFldNull(int colpos)=0;
 101 /*
 102     virtual void clearFldNull(const char *name)=0;
 103     virtual void clearFldNull(int colpos) =0;
 104 */
 105
 106     //DML operations
 107     /** executes the select statement. Based on the predicate(condition), respective index is
 108     * chosen for the select. Application should call execute before they start fetching
 109     * the values from the table.This starts scan on the table.
 110     * @returns DbRetVal
 111     */
 112     virtual DbRetVal execute()=0;
 113
 114     /** insert the tuple into the table. Prior to this, the binded buffer should be updated
 115     *  Values present in the binded buffers of all the fields are taken and stored in
 116     *  the table.<br/>
 117     * @returns DbRetVal
 118     */
 119     virtual DbRetVal insertTuple()=0;
 120
 121     /**update values in the current tuple of the table. It works only on top of select
 122     *  using fetch go to the tuple to be updated, then update the binded buffer value and
 123     *  then call this method to updates the field values in the tuple.
 124     * @returns DbRetVal
 125     */
 126     virtual DbRetVal updateTuple()=0;
 127
 128     /**deletes the current tuple of the table. It works only on top of select.
 129     *  using fetch first go to the tuple to be deleted, then call this method to delete.<br/>
 130     *  To delete all the tuples, do not set any condition and call fetch followed by delete
 131     *  in a loop till fetch exhausts.
 132     * @returns DbRetVal
 133     */
 134
 135     virtual DbRetVal deleteTuple()=0;
 136
 137
 138     /**deletes all the records which satisfies the condition set.
 139     * @returns int totalTuples deleted
 140     */
 141
 142     virtual int deleteWhere()=0;
 143
 144
 145
 146     /**deletes the all the records in the table. No transaction required to call this.
 147     *  It takes table level lock.
 148     * @returns DbRetVal
 149     */
 150
 151     virtual int truncate()=0;
 152
 153     //scan
 154
 155     /**fetches the next tuple in the table which satisfies the condition specified.
 156     * execute should be called before calling this method. Application buffer should be
 157     * binded to get the tuple values.
 158     * @returns void* NULL if there is no tuple.
 159     */
 160     virtual void* fetch()=0;
 161     virtual void* fetch(DbRetVal &rv)=0;
 162
 163     /**fetches the next tuple in the table which satisfies the condition specified.
 164     * execute should be called before calling this method. Application buffer need not be
 165     * binded to call this method.
 166     * @returns void* NULL if there is no tuple.
 167     */
 168     virtual void* fetchNoBind()=0;
 169     virtual void* fetchNoBind(DbRetVal &rv)=0;
 170
 171
 172     /**closes the scan. Needs to be called before calling execute again on the same table handle. It releases the resources
 173  acquired during the scan.
 174     * @returns DbRetVal
 175     */
 176
 177     virtual DbRetVal close()=0;
 178     virtual DbRetVal closeScan()=0;
 179
 180     /**Retrieves the total space used for this table in bytes
 181     * @returns DbRetVal
 182     */
 183     virtual long spaceUsed()=0;
 184
 185     /**Retrieves the total number of tuples present in this table
 186     * @returns DbRetVal
 187     */
 188     virtual long numTuples()=0;
 189
 190     /**takes lock on the table
 191     * if bool shared flag is set, it will take shared lock, or else exclusive lock
 192     * @returns DbRetVal
 193     */
 194     virtual DbRetVal lock(bool shared)=0;
 195
 196     /**releases the lock acquired on the table
 197     * @returns DbRetVal
 198     */
 199     virtual DbRetVal unlock()=0;
 200
 201     /**sets the undo log flag. If this flag is unset then undo logs will not be generated
 202     * @returns DbRetVal
 203     */
 204     virtual DbRetVal setUndoLogging(bool flag)=0;
 205
 206     virtual DbRetVal getFieldInfo(const char *fieldName, FieldInfo *&info)=0;
 207     virtual List getFieldNameList()=0;
 208     virtual char* getName()=0;
 209     virtual char* getAliasName()=0;
 210     virtual void printSQLIndexString(FILE *fp=NULL, int fd=-1)=0;
 211     virtual void printSQLForeignString()=0;
 212     virtual DbRetVal compact()=0;
 213     //optimizer
 214     virtual DbRetVal optimize()=0;
 215     virtual ScanType getScanType()=0;
 216     virtual bool hasIndex(char *name)=0;
 217     virtual bool isTableInvolved(char *tblName)=0;
 218     virtual bool pushPredicate(Predicate *pred)=0;
 219     virtual void setPredicate(Predicate *pred)=0;
 220     virtual void printPlan(int space)=0;
 221     virtual void addPredicate(char *fname, ComparisionOp op, void *buf)
 222                  { return; }
 223     virtual bool isFKTable()=0;
 224     virtual void resetNullinfo()=0;
 225     virtual int getFldPos(char *name)=0;
 226     virtual ~Table() { }
 227
 228     virtual void setLoading(bool flag){};
 229
 230     //non virtual functions
 231     static void getFieldNameAlone(char *fname, char *name);
 232     static void getTableNameAlone(char *fname, char *name);
 233 };
 234
 235 #endif