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Improved comments and variable names in infrastructure routines of UPDATE,

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DELETE, and INSERT.

FossilOrigin-Name: ad90e762e51384ac7c311f08a641419f03f6d3f0
This commit is contained in:
drh
2013-10-31 15:37:49 +00:00
parent 77f64bb7b9
commit 6934fc7b6f
6 changed files with 144 additions and 134 deletions
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51
src/delete.c
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@@ -523,24 +523,21 @@ delete_from_cleanup:
/*
** This routine generates VDBE code that causes a single row of a
** single table to be deleted.
** single table to be deleted. Both the original table entry and
** all indices are removed.
**
** The VDBE must be in a particular state when this routine is called.
** These are the requirements:
** Preconditions:
**
** 1. iDataCur is an open cursor on the btree that is the primary data
** repository for the table. This will be either the table itself,
** 1. iDataCur is an open cursor on the btree that is the canonical data
** store for the table. (This will be either the table itself,
** in the case of a rowid table, or the PRIMARY KEY index in the case
** of a WITHOUT ROWID table.
** of a WITHOUT ROWID table.)
**
** 2. Read/write cursors for all indices of pTab must be open as
** cursor number iIdxCur+i for the i-th index.
**
** 3. The primary key for the row to be deleted must be stored in a
** sequence of nPk memory cells starting at iPk.
**
** This routine generates code to remove both the table record and all
** index entries that point to that record.
*/
void sqlite3GenerateRowDelete(
Parse *pParse, /* Parsing context */
@@ -560,7 +557,7 @@ void sqlite3GenerateRowDelete(
/* Vdbe is guaranteed to have been allocated by this stage. */
assert( v );
VdbeModuleComment((v, "BEGIN: GenerateRowDelete(%d,%d,%d,%d)",
VdbeModuleComment((v, "BEGIN: GenRowDel(%d,%d,%d,%d)",
iDataCur, iIdxCur, iPk, (int)nPk));
/* Seek cursor iCur to the row to delete. If this row no longer exists
@@ -636,26 +633,26 @@ void sqlite3GenerateRowDelete(
** trigger programs were invoked. Or if a trigger program throws a
** RAISE(IGNORE) exception. */
sqlite3VdbeResolveLabel(v, iLabel);
VdbeModuleComment((v, "END: GenerateRowDelete()"));
VdbeModuleComment((v, "END: GenRowDel()"));
}
/*
** This routine generates VDBE code that causes the deletion of all
** index entries associated with a single row of a single table.
** index entries associated with a single row of a single table, pTab
**
** The VDBE must be in a particular state when this routine is called.
** These are the requirements:
** Preconditions:
**
** 1. A read/write cursor "iDataCur" pointing to canonical storage
** tree for the table pTab, which will be either the table itself
** 1. A read/write cursor "iDataCur" must be open on the canonical storage
** btree for the table pTab. (This will be either the table itself
** for rowid tables or to the primary key index for WITHOUT ROWID
** tables.
** tables.)
**
** 2. Read/write cursors for all indices of pTab must be open as
** cursor number iIdxCur+i for the i-th index.
** cursor number iIdxCur+i for the i-th index. (The pTab->pIndex
** index is the 0-th index.)
**
** 3. The "iDataCur" cursor must be pointing to the row that is to be
** deleted.
** 3. The "iDataCur" cursor must be already be positioned on the row
** that is to be deleted.
*/
void sqlite3GenerateRowIndexDelete(
Parse *pParse, /* Parsing and code generating context */
@@ -664,15 +661,17 @@ void sqlite3GenerateRowIndexDelete(
int iIdxCur, /* First index cursor */
int *aRegIdx /* Only delete if aRegIdx!=0 && aRegIdx[i]>0 */
){
int i;
Index *pIdx;
int r1;
int iPartIdxLabel;
Vdbe *v = pParse->pVdbe;
Index *pPk;
int i; /* Index loop counter */
int r1; /* Register holding an index key */
int iPartIdxLabel; /* Jump destination for skipping partial index entries */
Index *pIdx; /* Current index */
Vdbe *v; /* The prepared statement under construction */
Index *pPk; /* PRIMARY KEY index, or NULL for rowid tables */
v = pParse->pVdbe;
pPk = HasRowid(pTab) ? 0 : sqlite3PrimaryKeyIndex(pTab);
for(i=0, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
assert( iIdxCur+i!=iDataCur || pPk==pIdx );
if( aRegIdx!=0 && aRegIdx[i]==0 ) continue;
if( pIdx==pPk ) continue;
r1 = sqlite3GenerateIndexKey(pParse, pIdx, iDataCur, 0, 1, &iPartIdxLabel);