ING_DB
This commit is contained in:
Oliver Lehmann
parent
1696d51d0c
commit
9465ccdf03
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# include "gen.h"
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# include "../h/dbs.h"
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# include "../h/access.h"
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# define SAMETUP 0
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# define SAMEKEYS 1
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# define DIFFTUP 2
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/*
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** AAam_replace - replace an already existing tuple
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**
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** AAam_replace will replace the tuple specified by TID
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** with the new tuple. An attempt is made to not
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** move the tuple if at all possible.
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**
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** Three separate conditions are delt with. If the
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** new tuple is the same as the old tuple, a return
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** of zero occures and the page is not changed.
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**
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** If the keys(if any) are the same and the canonical
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** tuple lengths are the same, then the new tuple will
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** be placed in the same location.
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**
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** If the lengths or the keys are different, then the
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** tuple is deleted and the new tuple inserted
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**
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** Checkdups specifies whether to check for duplicates.
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** If the new tuple is a duplicate of one already there,
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** then the tuple at TID is deleted
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** returns:
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** <0 fatal error
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** 0 ok
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** 1 new tuple was duplicate of returned tid
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** 2 tuple not found, already deleted (TID invalid)
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**
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** If AAam_replace returns 1 then tid is set to the
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** duplicate tuple. This is necessary for updating
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** secondary indices.
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*/
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AAam_replace(d, tid, tuple, checkdups)
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register DESC *d;
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register struct tup_id *tid;
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char *tuple;
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int checkdups;
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{
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register int i;
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register int same;
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register int need;
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register int len;
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register int oldlength;
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char *new;
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char *old;
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char *oldt;
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struct tup_id primtid;
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long primpage;
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char oldtuple[MAXTUP];
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extern char *AAgetint_tuple();
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# ifdef xATR1
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if (AAtTfp(95, 0, "REPLACE: %.14s,", d->reldum.relid))
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{
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AAdumptid(tid);
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printf("REPLACE: ");
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AAprtup(d, tuple);
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}
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# endif
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/* make tuple canonical */
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need = AAcanonical(d, tuple);
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/* if heap, no dup checking */
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if (abs(ctoi(d->reldum.relspec)) == M_HEAP)
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checkdups = FALSE;
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if (i = AAgetpage(d, tid))
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return (i); /* fatal error */
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/* check if tid exists */
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if (i = AAinvalid(tid))
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return (i); /* already deleted or AAinvalid */
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oldt = AAgetint_tuple(d, tid, oldtuple);
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oldlength = AAtup_len(tid);
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/* check whether tuples are the same, different lengths, different keys */
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same = DIFFTUP; /* assume diff lengths or keys */
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if (oldlength == need)
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{
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/* same size. check for same domains */
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same = SAMETUP; /* assume identical */
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new = tuple;
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old = oldt;
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for (i = 1; i <= d->reldum.relatts; i++)
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{
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len = ctou(d->relfrml[i]);
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if (AAicompare(new, old, d->relfrmt[i], len))
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{
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if (d->relxtra[i])
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{
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same = DIFFTUP;
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break;
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}
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same = SAMEKEYS;
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}
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old += len;
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new += len;
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}
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}
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# ifdef xATR2
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AAtTfp(95, 1, "REPLACE: same=%d\n", same);
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# endif
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switch (same)
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{
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case SAMETUP: /* new tuple same as old tuple */
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i = 1; /* flag as duplicate */
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/* though character strings may compare equal,
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** they can look different, so if they do look different
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** go ahead and do the replace using AAput_tuple. */
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if (!AAbequal(tuple, oldt, d->reldum.relwid))
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goto puttuple;
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break;
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case SAMEKEYS: /* keys the same, lengths the same, tuples different */
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if (checkdups)
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{
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/* This is either an ISAM or HASH file. If mainpg
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** is non-zero, then the primary page = mainpg - 1.
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** Otherwise, "find" must be called to determine
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** the primary page
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*/
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if (AAcc_head->mainpg)
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{
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primpage = AAcc_head->mainpg - 1;
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AAstuff_page(&primtid, &primpage);
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}
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else
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{
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if (i = AAam_find(d, FULLKEY, &primtid, &primtid, tuple))
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return (i); /* fatal error */
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if (i = AAgetpage(d, tid)) /* restore page for tuple */
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return (i);
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}
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if (i = AAscan_dups(d, &primtid, tuple))
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{
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if (i == 1)
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{
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AAdel_tuple(tid, oldlength); /* tuple a duplicate */
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d->reladds--;
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/* copy tid of duplicate tuple */
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AAbmove(&primtid, tid, sizeof(primtid));
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}
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break;
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}
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}
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goto puttuple;
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case DIFFTUP: /* keys different or lengths different */
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AAdel_tuple(tid, oldlength);
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/* find where to put tuple */
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if (i = AAfindbest(d, tid, tuple, need, checkdups))
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{
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d->reladds--;
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break;
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}
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/* place new tuple in page */
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puttuple:
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AAput_tuple(tid, AAcctuple, need);
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i = 0;
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}
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# ifdef xATR1
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if (AAtTfp(95, 2, "REPLACE: rets %d,", i))
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AAdumptid(tid);
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# endif
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return (i);
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}
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