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Overview
Comment:Add missing comments and make some code on this branch clearer.
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SHA1: 6937677cc2c2db6b21f997559f88a339466cd15b
User & Date: dan 2016-08-02 16:18:35
Context
2016-08-02
16:24
Merge latest trunk changes into this branch. check-in: d468101b user: dan tags: rowvalue
16:18
Add missing comments and make some code on this branch clearer. check-in: 6937677c user: dan tags: rowvalue
2016-08-01
20:14
Fix a problem with vector range constraints involving the rowid column. And other issues. check-in: 3ef75d45 user: dan tags: rowvalue
Changes
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Changes to src/whereexpr.c.

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**
** If pExpr is a TK_COLUMN column reference, then this routine always returns
** true even if that particular column is not indexed, because the column
** might be added to an automatic index later.
*/
static int exprMightBeIndexed(
  SrcList *pFrom,        /* The FROM clause */
  int op,
  Bitmask mPrereq,       /* Bitmask of FROM clause terms referenced by pExpr */
  Expr *pExpr,           /* An operand of a comparison operator */
  int *piCur,            /* Write the referenced table cursor number here */
  int *piColumn          /* Write the referenced table column number here */
){
  Index *pIdx;
  int i;
................................................................................
      pTerm = &pWC->a[idxTerm];
      pTerm->wtFlags |= TERM_COPIED;
      pNewTerm->prereqAll = pTerm->prereqAll;
    }
  }
#endif /* SQLITE_OMIT_VIRTUALTABLE */





  if( pWC->op==TK_AND 
  && (pExpr->op==TK_EQ || pExpr->op==TK_IS)
  && sqlite3ExprIsVector(pExpr->pLeft)
  && ( (pExpr->pLeft->flags & EP_xIsSelect)==0 
    || (pExpr->pRight->flags & EP_xIsSelect)==0
  )){
    int nLeft = sqlite3ExprVectorSize(pExpr->pLeft);
................................................................................
        idxNew = whereClauseInsert(pWC, pNew, TERM_VIRTUAL|TERM_DYNAMIC);
        exprAnalyze(pSrc, pWC, idxNew);
        markTermAsChild(pWC, idxNew, idxTerm);
      }
    }
  }






  if( pWC->op==TK_AND && pExpr->op==TK_IN && pTerm->iField==0
   && pExpr->pLeft->op==TK_VECTOR
  ){
    int i;
    for(i=0; i<sqlite3ExprVectorSize(pExpr->pLeft); i++){
      int idxNew;
      idxNew = whereClauseInsert(pWC, pExpr, TERM_VIRTUAL);







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**
** If pExpr is a TK_COLUMN column reference, then this routine always returns
** true even if that particular column is not indexed, because the column
** might be added to an automatic index later.
*/
static int exprMightBeIndexed(
  SrcList *pFrom,        /* The FROM clause */
  int op,                /* The specific comparison operator */
  Bitmask mPrereq,       /* Bitmask of FROM clause terms referenced by pExpr */
  Expr *pExpr,           /* An operand of a comparison operator */
  int *piCur,            /* Write the referenced table cursor number here */
  int *piColumn          /* Write the referenced table column number here */
){
  Index *pIdx;
  int i;
................................................................................
      pTerm = &pWC->a[idxTerm];
      pTerm->wtFlags |= TERM_COPIED;
      pNewTerm->prereqAll = pTerm->prereqAll;
    }
  }
#endif /* SQLITE_OMIT_VIRTUALTABLE */

  /* If there is a vector == or IS term - e.g. "(a, b) == (?, ?)" - create
  ** a virtual term for each component comparison - "a = ?" and "b = ?".
  ** This is only required if at least one side of the comparison operation
  ** is not a sub-select.  */
  if( pWC->op==TK_AND 
  && (pExpr->op==TK_EQ || pExpr->op==TK_IS)
  && sqlite3ExprIsVector(pExpr->pLeft)
  && ( (pExpr->pLeft->flags & EP_xIsSelect)==0 
    || (pExpr->pRight->flags & EP_xIsSelect)==0
  )){
    int nLeft = sqlite3ExprVectorSize(pExpr->pLeft);
................................................................................
        idxNew = whereClauseInsert(pWC, pNew, TERM_VIRTUAL|TERM_DYNAMIC);
        exprAnalyze(pSrc, pWC, idxNew);
        markTermAsChild(pWC, idxNew, idxTerm);
      }
    }
  }

  /* If there is a vector IN term - e.g. "(a, b) IN (SELECT ...)" - create
  ** a virtual term for each vector component. The expression object
  ** used by each such virtual term is pExpr (the full vector IN(...) 
  ** expression). The WhereTerm.iField variable identifies the index within
  ** the vector on the LHS that the virtual term represents.  */
  if( pWC->op==TK_AND && pExpr->op==TK_IN && pTerm->iField==0
   && pExpr->pLeft->op==TK_VECTOR
  ){
    int i;
    for(i=0; i<sqlite3ExprVectorSize(pExpr->pLeft); i++){
      int idxNew;
      idxNew = whereClauseInsert(pWC, pExpr, TERM_VIRTUAL);