1: # include   <ingres.h>
   2: # include   <aux.h>
   3: # include   <symbol.h>
   4: # include   <access.h>
   5: # include   <lock.h>
   6: # include   <btree.h>
   7: # include   <sccs.h>
   8: 
   9: SCCSID(@(#)find.c	8.1	12/31/84)
  10: 
  11: 
  12: /*
  13: **	Find - determine limits for scan of a relation
  14: **
  15: **	Find determines the values of an initial TID
  16: **	and an ending TID for scanning a relation.
  17: **	The possible calls to find are:
  18: **
  19: **	find(desc, NOKEY, lotid, hightid)
  20: **		sets tids to scan entire relation
  21: **
  22: **	find(desc, EXACTKEY, lotid, hightid, key)
  23: **		sets tids according to structure
  24: **		of the relation. Key should have
  25: **		been build using setkey.
  26: **
  27: **	find(desc, LRANGEKEY, lotid, hightid, keylow)
  28: **		Finds lotid less then or equal to keylow
  29: **		for isam relations. Otherwise scans whole relation.
  30: **		This call should be followed by a call with HRANGEKEY.
  31: **
  32: **	find(desc, HRANGEKEY, lotid, hightid, keyhigh)
  33: **		Finds hightid greater than or equal to
  34: **		keyhigh for isam relations. Otherwise sets
  35: **		hightid to maximum scan.
  36: **
  37: **	find(desc, FULLKEY, lotid, hightid, key)
  38: **		Same as find with EXACTKEY and all keys
  39: **		provided. This mode is used only by findbest
  40: **		and replace.
  41: **
  42: **	returns:
  43: **		<0 fatal error
  44: **		 0 success
  45: **
  46: **	Trace Flags:
  47: **		22.0-8
  48: */
  49: 
  50: 
  51: find(d, mode, lotid, hightid, key)
  52: register DESC   *d;
  53: int     mode;
  54: TID     *lotid;
  55: TID     *hightid;
  56: char        *key;
  57: {
  58:     register int    ret;
  59:     bool        keyok;
  60:     long        pageid, lid[MAXLID], page;
  61:     long        rhash(), get_tid();
  62:     struct locator  tid_id;
  63:     char        *tp;
  64:     int     i;
  65:     extern int  Btree_fd;
  66: 
  67: #	ifdef xATR1
  68:     if (tTf(22, 0))
  69:     {
  70:         printf("find: m%d,s%d,%.14s\n", mode, d->reldum.relspec, d->reldum.relid);
  71:         if (mode != NOKEY)
  72:             printup(d, key);
  73:     }
  74: #	endif
  75: 
  76:     ret = 0;    /* assume successful return */
  77:     keyok = FALSE;
  78: 
  79:     switch (mode)
  80:     {
  81: 
  82:       case EXACTKEY:
  83:         keyok = fullkey(d);
  84:         break;
  85: 
  86:       case FULLKEY:
  87:         keyok = TRUE;
  88: 
  89:       case NOKEY:
  90:       case LRANGEKEY:
  91:       case HRANGEKEY:
  92:       case BTREEKEY:
  93:         break;
  94: 
  95:       default:
  96:         syserr("FIND: bad mode %d", mode);
  97:     }
  98: 
  99:     /* set lotid for beginning of scan */
 100:     if (mode != HRANGEKEY)
 101:     {
 102:         pageid = 0;
 103:         stuff_page(lotid, &pageid);
 104:         lotid->line_id = -1;
 105:     }
 106: 
 107:     /* set hitid for end of scan */
 108:     if (mode != LRANGEKEY)
 109:     {
 110:         pageid = -1;
 111:         stuff_page(hightid, &pageid);
 112:         hightid->line_id = -1;
 113:     }
 114: 
 115:     if (mode == BTREEKEY)
 116:     /* set tid to value as found using B-Tree */
 117:     {
 118:         tp = key + d->reldum.relwid - LIDSIZE * d->reldum.reldim;
 119:         bmove(tp, lid, LIDSIZE * d->reldum.reldim);
 120:         Btree_fd = d->btree_fd;
 121:         page = RT;
 122:         for (i = 0; i < d->reldum.reldim; ++i)
 123:         {
 124:             pageid = get_tid(page, lid[i], &tid_id);
 125:             if (pageid < 0)
 126:                 break;
 127:             page = pageid;
 128:         }
 129:         if (pageid >= 0)
 130:             bmove(&pageid, lotid, LIDSIZE);
 131: 
 132:     }
 133:     else if (mode != NOKEY)
 134:     {
 135:         switch (abs(d->reldum.relspec))
 136:         {
 137: 
 138:           case M_HEAP:
 139:             break;
 140: 
 141:           case M_ISAM:
 142:             if (mode != HRANGEKEY)
 143:             {
 144:                 /* compute lo limit */
 145:                 if (ret = ndxsearch(d, lotid, key, -1, keyok))
 146:                     break;  /* fatal error */
 147:             }
 148: 
 149:             /* if the full key was provided and mode is exact, then done */
 150:             if (keyok)
 151:             {
 152:                 bmove((char *) lotid, (char *) hightid, sizeof *lotid);
 153:                 break;
 154:             }
 155: 
 156:             if (mode != LRANGEKEY)
 157:                 ret = ndxsearch(d, hightid, key, 1, keyok);
 158:             break;
 159: 
 160:           case M_HASH:
 161:             if (!keyok)
 162:                 break;      /* can't do anything */
 163:             pageid = rhash(d, key);
 164:             stuff_page(lotid, &pageid);
 165:             stuff_page(hightid, &pageid);
 166:             break;
 167: 
 168:           default:
 169:             ret = acc_err(AMFIND_ERR);
 170:         }
 171:     }
 172: 
 173: #	ifdef xATR2
 174:     if (tTf(22, 1))
 175:     {
 176:         printf("find: ret %d\tlow", ret);
 177:         dumptid(lotid);
 178:         printf("hi");
 179:         dumptid(hightid);
 180:     }
 181: #	endif
 182:     return (ret);
 183: }
 184: /*
 185: ** This routine will check that enough of the tuple has been specified
 186: ** to enable a key access.
 187: */
 188: 
 189: fullkey(des)
 190: DESC    *des;
 191: {
 192:     register DESC   *d;
 193:     register int    i;
 194: 
 195:     d = des;
 196:     for (i = 1; i <= d->reldum.relatts; i++)
 197:         if (d->relxtra[i] && !d->relgiven[i])
 198:             return (FALSE);
 199:     return (TRUE);
 200: }

Defined functions

fullkey defined in line 189; used 1 times
  • in line 83
Last modified: 1986-04-17
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