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Overview
Comment:Simplification of the DROP TRIGGER logic using sqlite3NestedParse() instead of hand-coded VDBE code. This is a manual cherry-pick of the key change from check-in [c80bbf14b365d].
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SHA1: 8021b4c8139ba56d6b1e2e26aeec4f9bf77f37c9
User & Date: drh 2015-12-09 16:26:38.759
Context
2015-12-09
17:23
Further simplifications to the VDBE code generation logic that flow out of the previous check-in. (check-in: 6a5dfe85b5 user: drh tags: trunk)
16:26
Simplification of the DROP TRIGGER logic using sqlite3NestedParse() instead of hand-coded VDBE code. This is a manual cherry-pick of the key change from check-in [c80bbf14b365d]. (check-in: 8021b4c813 user: drh tags: trunk)
2015-12-08
16:58
Changes to avoid undefined behavior in memset() and memcpy() and in the comparisons of pointers from different allocations. All problems are found by analysis tools - none have been seen in the wild. (check-in: 901d0b8f3b user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/trigger.c.
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  }
#endif

  /* Generate code to destroy the database record of the trigger.
  */
  assert( pTable!=0 );
  if( (v = sqlite3GetVdbe(pParse))!=0 ){
    int base;
    static const int iLn = VDBE_OFFSET_LINENO(2);
    static const VdbeOpList dropTrigger[] = {
      { OP_Rewind,     0, ADDR(9),  0},
      { OP_String8,    0, 1,        0}, /* 1 */
      { OP_Column,     0, 1,        2},
      { OP_Ne,         2, ADDR(8),  1},
      { OP_String8,    0, 1,        0}, /* 4: "trigger" */
      { OP_Column,     0, 0,        2},
      { OP_Ne,         2, ADDR(8),  1},
      { OP_Delete,     0, 0,        0},
      { OP_Next,       0, ADDR(1),  0}, /* 8 */
    };

    sqlite3BeginWriteOperation(pParse, 0, iDb);
    sqlite3OpenMasterTable(pParse, iDb);
    base = sqlite3VdbeAddOpList(v,  ArraySize(dropTrigger), dropTrigger, iLn);
    sqlite3VdbeChangeP4(v, base+1, pTrigger->zName, P4_TRANSIENT);
    sqlite3VdbeChangeP4(v, base+4, "trigger", P4_STATIC);

    sqlite3ChangeCookie(pParse, iDb);
    sqlite3VdbeAddOp2(v, OP_Close, 0, 0);
    sqlite3VdbeAddOp4(v, OP_DropTrigger, iDb, 0, 0, pTrigger->zName, 0);
    if( pParse->nMem<3 ){
      pParse->nMem = 3;
    }
  }
}

/*
** Remove a trigger from the hash tables of the sqlite* pointer.
*/
void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){








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  }
#endif

  /* Generate code to destroy the database record of the trigger.
  */
  assert( pTable!=0 );
  if( (v = sqlite3GetVdbe(pParse))!=0 ){
    sqlite3NestedParse(pParse,












       "DELETE FROM %Q.%s WHERE name=%Q AND type='trigger'",



       db->aDb[iDb].zName, SCHEMA_TABLE(iDb), pTrigger->zName

    );
    sqlite3ChangeCookie(pParse, iDb);

    sqlite3VdbeAddOp4(v, OP_DropTrigger, iDb, 0, 0, pTrigger->zName, 0);



  }
}

/*
** Remove a trigger from the hash tables of the sqlite* pointer.
*/
void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){
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