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sqlcipher/src/delete.c at sqlite-release · securitykernel/sqlcipher · GitHub
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/*
** 2001 September 15
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** in order to generate code for DELETE FROM statements.
*/
#include
"sqliteInt.h"
/*
** While a SrcList can in general represent multiple tables and subqueries
** (as in the FROM clause of a SELECT statement) in this case it contains
** the name of a single table, as one might find in an INSERT, DELETE,
** or UPDATE statement. Look up that table in the symbol table and
** return a pointer. Set an error message and return NULL if the table
** name is not found or if any other error occurs.
**
** The following fields are initialized appropriate in pSrc:
**
** pSrc->a[0].pTab Pointer to the Table object
** pSrc->a[0].pIndex Pointer to the INDEXED BY index, if there is one
**
*/
Table
*
sqlite3SrcListLookup
(
Parse
*
pParse
,
SrcList
*
pSrc
){
struct
SrcList_item
*
pItem
=
pSrc
->
a
;
Table
*
pTab
;
assert
(
pItem
&&
pSrc
->
nSrc
==
1
);
pTab
=
sqlite3LocateTableItem
(
pParse
,
0
,
pItem
);
sqlite3DeleteTable
(
pParse
->
db
,
pItem
->
pTab
);
pItem
->
pTab
=
pTab
;
if
(
pTab
){
pTab
->
nTabRef
++
;
}
if
(
sqlite3IndexedByLookup
(
pParse
,
pItem
) ){
pTab
=
0
;
}
return
pTab
;
}
/* Return true if table pTab is read-only.
**
** A table is read-only if any of the following are true:
**
** 1) It is a virtual table and no implementation of the xUpdate method
** has been provided
**
** 2) It is a system table (i.e. sqlite_master), this call is not
** part of a nested parse and writable_schema pragma has not
** been specified
**
** 3) The table is a shadow table, the database connection is in
** defensive mode, and the current sqlite3_prepare()
** is for a top-level SQL statement.
*/
static
int
tabIsReadOnly
(
Parse
*
pParse
,
Table
*
pTab
){
sqlite3
*
db
;
if
(
IsVirtual
(
pTab
) ){
return
sqlite3GetVTable
(
pParse
->
db
,
pTab
)
->
pMod
->
pModule
->
xUpdate
==
0
;
}
if
( (
pTab
->
tabFlags
&
(
TF_Readonly
|
TF_Shadow
))
==
0
)
return
0
;
db
=
pParse
->
db
;
if
( (
pTab
->
tabFlags
&
TF_Readonly
)
!=
0
){
return
sqlite3WritableSchema
(
db
)
==
0
&&
pParse
->
nested
==
0
;
}
assert
(
pTab
->
tabFlags
&
TF_Shadow
);
return
sqlite3ReadOnlyShadowTables
(
db
);
}
/*
** Check to make sure the given table is writable. If it is not
** writable, generate an error message and return 1. If it is
** writable return 0;
*/
int
sqlite3IsReadOnly
(
Parse
*
pParse
,
Table
*
pTab
,
int
viewOk
){
if
(
tabIsReadOnly
(
pParse
,
pTab
) ){
sqlite3ErrorMsg
(
pParse
,
"table %s may not be modified"
,
pTab
->
zName
);
return
1
;
}
#ifndef
SQLITE_OMIT_VIEW
if
( !
viewOk
&&
pTab
->
pSelect
){
sqlite3ErrorMsg
(
pParse
,
"cannot modify %s because it is a view"
,
pTab
->
zName
);
return
1
;
}
#endif
return
0
;
}
#if
!defined(
SQLITE_OMIT_VIEW
)
&&
!defined(
SQLITE_OMIT_TRIGGER
)
/*
** Evaluate a view and store its result in an ephemeral table. The
** pWhere argument is an optional WHERE clause that restricts the
** set of rows in the view that are to be added to the ephemeral table.
*/
void
sqlite3MaterializeView
(
Parse
*
pParse
,
/* Parsing context */
Table
*
pView
,
/* View definition */
Expr
*
pWhere
,
/* Optional WHERE clause to be added */
ExprList
*
pOrderBy
,
/* Optional ORDER BY clause */
Expr
*
pLimit
,
/* Optional LIMIT clause */
int
iCur
/* Cursor number for ephemeral table */
){
SelectDest
dest
;
Select
*
pSel
;
SrcList
*
pFrom
;
sqlite3
*
db
=
pParse
->
db
;
int
iDb
=
sqlite3SchemaToIndex
(
db
,
pView
->
pSchema
);
pWhere
=
sqlite3ExprDup
(
db
,
pWhere
,
0
);
pFrom
=
sqlite3SrcListAppend
(
pParse
,
0
,
0
,
0
);
if
(
pFrom
){
assert
(
pFrom
->
nSrc
==
1
);
pFrom
->
a
[
0
].
zName
=
sqlite3DbStrDup
(
db
,
pView
->
zName
);
pFrom
->
a
[
0
].
zDatabase
=
sqlite3DbStrDup
(
db
,
db
->
aDb
[
iDb
].
zDbSName
);
assert
(
pFrom
->
a
[
0
].
pOn
==
0
);
assert
(
pFrom
->
a
[
0
].
pUsing
==
0
);
}
pSel
=
sqlite3SelectNew
(
pParse
,
0
,
pFrom
,
pWhere
,
0
,
0
,
pOrderBy
,
SF_IncludeHidden
,
pLimit
);
sqlite3SelectDestInit
(
&
dest
,
SRT_EphemTab
,
iCur
);
sqlite3Select
(
pParse
,
pSel
,
&
dest
);
sqlite3SelectDelete
(
db
,
pSel
);
}
#endif
/* !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER) */
#if
defined(
SQLITE_ENABLE_UPDATE_DELETE_LIMIT
)
&&
!defined(
SQLITE_OMIT_SUBQUERY
)
/*
** Generate an expression tree to implement the WHERE, ORDER BY,
** and LIMIT/OFFSET portion of DELETE and UPDATE statements.
**
** DELETE FROM table_wxyz WHERE a<5 ORDER BY a LIMIT 1;
** \__________________________/
** pLimitWhere (pInClause)
*/
Expr
*
sqlite3LimitWhere
(
Parse
*
pParse
,
/* The parser context */
SrcList
*
pSrc
,
/* the FROM clause -- which tables to scan */
Expr
*
pWhere
,
/* The WHERE clause. May be null */
ExprList
*
pOrderBy
,
/* The ORDER BY clause. May be null */
Expr
*
pLimit
,
/* The LIMIT clause. May be null */
char
*
zStmtType
/* Either DELETE or UPDATE. For err msgs. */
){
sqlite3
*
db
=
pParse
->
db
;
Expr
*
pLhs
=
NULL
;
/* LHS of IN(SELECT...) operator */
Expr
*
pInClause
=
NULL
;
/* WHERE rowid IN ( select ) */
ExprList
*
pEList
=
NULL
;
/* Expression list contaning only pSelectRowid */
SrcList
*
pSelectSrc
=
NULL
;
/* SELECT rowid FROM x ... (dup of pSrc) */
Select
*
pSelect
=
NULL
;
/* Complete SELECT tree */
Table
*
pTab
;
/* Check that there isn't an ORDER BY without a LIMIT clause.
*/
if
(
pOrderBy
&&
pLimit
==
0
) {
sqlite3ErrorMsg
(
pParse
,
"ORDER BY without LIMIT on %s"
,
zStmtType
);
sqlite3ExprDelete
(
pParse
->
db
,
pWhere
);
sqlite3ExprListDelete
(
pParse
->
db
,
pOrderBy
);
return
0
;
}
/* We only need to generate a select expression if there
** is a limit/offset term to enforce.
*/
if
(
pLimit
==
0
) {
return
pWhere
;
}
/* Generate a select expression tree to enforce the limit/offset
** term for the DELETE or UPDATE statement. For example:
** DELETE FROM table_a WHERE col1=1 ORDER BY col2 LIMIT 1 OFFSET 1
** becomes:
** DELETE FROM table_a WHERE rowid IN (
** SELECT rowid FROM table_a WHERE col1=1 ORDER BY col2 LIMIT 1 OFFSET 1
** );
*/
pTab
=
pSrc
->
a
[
0
].
pTab
;
if
(
HasRowid
(
pTab
) ){
pLhs
=
sqlite3PExpr
(
pParse
,
TK_ROW
,
0
,
0
);
pEList
=
sqlite3ExprListAppend
(
pParse
,
0
,
sqlite3PExpr
(
pParse
,
TK_ROW
,
0
,
0
)
);
}
else
{
Index
*
pPk
=
sqlite3PrimaryKeyIndex
(
pTab
);
if
(
pPk
->
nKeyCol
==
1
){
const
char
*
zName
=
pTab
->
aCol
[
pPk
->
aiColumn
[
0
]].
zName
;
pLhs
=
sqlite3Expr
(
db
,
TK_ID
,
zName
);
pEList
=
sqlite3ExprListAppend
(
pParse
,
0
,
sqlite3Expr
(
db
,
TK_ID
,
zName
));
}
else
{
int
i
;
for
(
i
=
0
;
i
<
pPk
->
nKeyCol
;
i
++
){
Expr
*
p
=
sqlite3Expr
(
db
,
TK_ID
,
pTab
->
aCol
[
pPk
->
aiColumn
[
i
]].
zName
);
pEList
=
sqlite3ExprListAppend
(
pParse
,
pEList
,
p
);
}
pLhs
=
sqlite3PExpr
(
pParse
,
TK_VECTOR
,
0
,
0
);
if
(
pLhs
){
pLhs
->
x
.
pList
=
sqlite3ExprListDup
(
db
,
pEList
,
0
);
}
}
}
/* duplicate the FROM clause as it is needed by both the DELETE/UPDATE tree
** and the SELECT subtree. */
pSrc
->
a
[
0
].
pTab
=
0
;
pSelectSrc
=
sqlite3SrcListDup
(
pParse
->
db
,
pSrc
,
0
);
pSrc
->
a
[
0
].
pTab
=
pTab
;
pSrc
->
a
[
0
].
pIBIndex
=
0
;
/* generate the SELECT expression tree. */
pSelect
=
sqlite3SelectNew
(
pParse
,
pEList
,
pSelectSrc
,
pWhere
,
0
,
0
,
pOrderBy
,
0
,
pLimit
);
/* now generate the new WHERE rowid IN clause for the DELETE/UDPATE */
pInClause
=
sqlite3PExpr
(
pParse
,
TK_IN
,
pLhs
,
0
);
sqlite3PExprAddSelect
(
pParse
,
pInClause
,
pSelect
);
return
pInClause
;
}
#endif
/* defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) */
/* && !defined(SQLITE_OMIT_SUBQUERY) */
/*
** Generate code for a DELETE FROM statement.
**
** DELETE FROM table_wxyz WHERE a<5 AND b NOT NULL;
** \________/ \________________/
** pTabList pWhere
*/
void
sqlite3DeleteFrom
(
Parse
*
pParse
,
/* The parser context */
SrcList
*
pTabList
,
/* The table from which we should delete things */
Expr
*
pWhere
,
/* The WHERE clause. May be null */
ExprList
*
pOrderBy
,
/* ORDER BY clause. May be null */
Expr
*
pLimit
/* LIMIT clause. May be null */
){
Vdbe
*
v
;
/* The virtual database engine */
Table
*
pTab
;
/* The table from which records will be deleted */
int
i
;
/* Loop counter */
WhereInfo
*
pWInfo
;
/* Information about the WHERE clause */
Index
*
pIdx
;
/* For looping over indices of the table */
int
iTabCur
;
/* Cursor number for the table */
int
iDataCur
=
0
;
/* VDBE cursor for the canonical data source */
int
iIdxCur
=
0
;
/* Cursor number of the first index */
int
nIdx
;
/* Number of indices */
sqlite3
*
db
;
/* Main database structure */
AuthContext
sContext
;
/* Authorization context */
NameContext
sNC
;
/* Name context to resolve expressions in */
int
iDb
;
/* Database number */
int
memCnt
=
0
;
/* Memory cell used for change counting */
int
rcauth
;
/* Value returned by authorization callback */
int
eOnePass
;
/* ONEPASS_OFF or _SINGLE or _MULTI */
int
aiCurOnePass
[
2
];
/* The write cursors opened by WHERE_ONEPASS */
u8
*
aToOpen
=
0
;
/* Open cursor iTabCur+j if aToOpen[j] is true */
Index
*
pPk
;
/* The PRIMARY KEY index on the table */
int
iPk
=
0
;
/* First of nPk registers holding PRIMARY KEY value */
i16
nPk
=
1
;
/* Number of columns in the PRIMARY KEY */
int
iKey
;
/* Memory cell holding key of row to be deleted */
i16
nKey
;
/* Number of memory cells in the row key */
int
iEphCur
=
0
;
/* Ephemeral table holding all primary key values */
int
iRowSet
=
0
;
/* Register for rowset of rows to delete */
int
addrBypass
=
0
;
/* Address of jump over the delete logic */
int
addrLoop
=
0
;
/* Top of the delete loop */
int
addrEphOpen
=
0
;
/* Instruction to open the Ephemeral table */
int
bComplex
;
/* True if there are triggers or FKs or
** subqueries in the WHERE clause */
#ifndef
SQLITE_OMIT_TRIGGER
int
isView
;
/* True if attempting to delete from a view */
Trigger
*
pTrigger
;
/* List of table triggers, if required */
#endif
memset
(
&
sContext
,
0
,
sizeof
(
sContext
));
db
=
pParse
->
db
;
if
(
pParse
->
nErr
||
db
->
mallocFailed
){
goto
delete_from_cleanup
;
}
assert
(
pTabList
->
nSrc
==
1
);
/* Locate the table which we want to delete. This table has to be
** put in an SrcList structure because some of the subroutines we
** will be calling are designed to work with multiple tables and expect
** an SrcList* parameter instead of just a Table* parameter.
*/
pTab
=
sqlite3SrcListLookup
(
pParse
,
pTabList
);
if
(
pTab
==
0
) goto
delete_from_cleanup
;
/* Figure out if we have any triggers and if the table being
** deleted from is a view
*/
#ifndef
SQLITE_OMIT_TRIGGER
pTrigger
=
sqlite3TriggersExist
(
pParse
,
pTab
,
TK_DELETE
,
0
,
0
);
isView
=
pTab
->
pSelect
!=
0
;
#else
# define
pTrigger
0
# define
isView
0
#endif
bComplex
=
pTrigger
||
sqlite3FkRequired
(
pParse
,
pTab
,
0
,
0
);
#ifdef
SQLITE_OMIT_VIEW
# undef
isView
# define
isView
0
#endif
#ifdef
SQLITE_ENABLE_UPDATE_DELETE_LIMIT
if
( !
isView
){
pWhere
=
sqlite3LimitWhere
(
pParse
,
pTabList
,
pWhere
,
pOrderBy
,
pLimit
,
"DELETE"
);
pOrderBy
=
0
;
pLimit
=
0
;
}
#endif
/* If pTab is really a view, make sure it has been initialized.
*/
if
(
sqlite3ViewGetColumnNames
(
pParse
,
pTab
) ){
goto
delete_from_cleanup
;
}
if
(
sqlite3IsReadOnly
(
pParse
,
pTab
, (
pTrigger
?
1
:
0
)) ){
goto
delete_from_cleanup
;
}
iDb
=
sqlite3SchemaToIndex
(
db
,
pTab
->
pSchema
);
assert
(
iDb
<
db
->
nDb
);
rcauth
=
sqlite3AuthCheck
(
pParse
,
SQLITE_DELETE
,
pTab
->
zName
,
0
,
db
->
aDb
[
iDb
].
zDbSName
);
assert
(
rcauth
==
SQLITE_OK
||
rcauth
==
SQLITE_DENY
||
rcauth
==
SQLITE_IGNORE
);
if
(
rcauth
==
SQLITE_DENY
){
goto
delete_from_cleanup
;
}
assert
(!
isView
||
pTrigger
);
/* Assign cursor numbers to the table and all its indices.
*/
assert
(
pTabList
->
nSrc
==
1
);
iTabCur
=
pTabList
->
a
[
0
].
iCursor
=
pParse
->
nTab
++
;
for
(
nIdx
=
0
,
pIdx
=
pTab
->
pIndex
;
pIdx
;
pIdx
=
pIdx
->
pNext
,
nIdx
++
){
pParse
->
nTab
++
;
}
/* Start the view context
*/
if
(
isView
){
sqlite3AuthContextPush
(
pParse
,
&
sContext
,
pTab
->
zName
);
}
/* Begin generating code.
*/
v
=
sqlite3GetVdbe
(
pParse
);
if
(
v
==
0
){
goto
delete_from_cleanup
;
}
if
(
pParse
->
nested
==
0
)
sqlite3VdbeCountChanges
(
v
);
sqlite3BeginWriteOperation
(
pParse
,
bComplex
,
iDb
);
/* If we are trying to delete from a view, realize that view into
** an ephemeral table.
*/
#if
!defined(
SQLITE_OMIT_VIEW
)
&&
!defined(
SQLITE_OMIT_TRIGGER
)
if
(
isView
){
sqlite3MaterializeView
(
pParse
,
pTab
,
pWhere
,
pOrderBy
,
pLimit
,
iTabCur
);
iDataCur
=
iIdxCur
=
iTabCur
;
pOrderBy
=
0
;
pLimit
=
0
;
}
#endif
/* Resolve the column names in the WHERE clause.
*/
memset
(
&
sNC
,
0
,
sizeof
(
sNC
));
sNC
.
pParse
=
pParse
;
sNC
.
pSrcList
=
pTabList
;
if
(
sqlite3ResolveExprNames
(
&
sNC
,
pWhere
) ){
goto
delete_from_cleanup
;
}
/* Initialize the counter of the number of rows deleted, if
** we are counting rows.
*/
if
( (
db
->
flags
&
SQLITE_CountRows
)
!=
0
&&
!
pParse
->
nested
&&
!
pParse
->
pTriggerTab
){
memCnt
=
++
pParse
->
nMem
;
sqlite3VdbeAddOp2
(
v
,
OP_Integer
,
0
,
memCnt
);
}
#ifndef
SQLITE_OMIT_TRUNCATE_OPTIMIZATION
/* Special case: A DELETE without a WHERE clause deletes everything.
** It is easier just to erase the whole table. Prior to version 3.6.5,
** this optimization caused the row change count (the value returned by
** API function sqlite3_count_changes) to be set incorrectly.
**
** The "rcauth==SQLITE_OK" terms is the
** IMPLEMENTATION-OF: R-17228-37124 If the action code is SQLITE_DELETE and
** the callback returns SQLITE_IGNORE then the DELETE operation proceeds but
** the truncate optimization is disabled and all rows are deleted
** individually.
*/
if
(
rcauth
==
SQLITE_OK
&&
pWhere
==
0
&&
!
bComplex
&&
!
IsVirtual
(
pTab
)
#ifdef
SQLITE_ENABLE_PREUPDATE_HOOK
&&
db
->
xPreUpdateCallback
==
0
#endif
){
assert
( !
isView
);
sqlite3TableLock
(
pParse
,
iDb
,
pTab
->
tnum
,
1
,
pTab
->
zName
);
if
(
HasRowid
(
pTab
) ){
sqlite3VdbeAddOp4
(
v
,
OP_Clear
,
pTab
->
tnum
,
iDb
,
memCnt
?
memCnt
:
-1
,
pTab
->
zName
,
P4_STATIC
);
}
for
(
pIdx
=
pTab
->
pIndex
;
pIdx
;
pIdx
=
pIdx
->
pNext
){
assert
(
pIdx
->
pSchema
==
pTab
->
pSchema
);
sqlite3VdbeAddOp2
(
v
,
OP_Clear
,
pIdx
->
tnum
,
iDb
);
}
}
else
#endif
/* SQLITE_OMIT_TRUNCATE_OPTIMIZATION */
{
u16
wcf
=
WHERE_ONEPASS_DESIRED
|
WHERE_DUPLICATES_OK
|
WHERE_SEEK_TABLE
;
if
(
sNC
.
ncFlags
&
NC_VarSelect
)
bComplex
=
1
;
wcf
|= (
bComplex
?
0
:
WHERE_ONEPASS_MULTIROW
);
if
(
HasRowid
(
pTab
) ){
/* For a rowid table, initialize the RowSet to an empty set */
pPk
=
0
;
nPk
=
1
;
iRowSet
=
++
pParse
->
nMem
;
sqlite3VdbeAddOp2
(
v
,
OP_Null
,
0
,
iRowSet
);
}
else
{
/* For a WITHOUT ROWID table, create an ephemeral table used to
** hold all primary keys for rows to be deleted. */
pPk
=
sqlite3PrimaryKeyIndex
(
pTab
);
assert
(
pPk
!=
0
);
nPk
=
pPk
->
nKeyCol
;
iPk
=
pParse
->
nMem
+
1
;
pParse
->
nMem
+=
nPk
;
iEphCur
=
pParse
->
nTab
++
;
addrEphOpen
=
sqlite3VdbeAddOp2
(
v
,
OP_OpenEphemeral
,
iEphCur
,
nPk
);
sqlite3VdbeSetP4KeyInfo
(
pParse
,
pPk
);
}
/* Construct a query to find the rowid or primary key for every row
** to be deleted, based on the WHERE clause. Set variable eOnePass
** to indicate the strategy used to implement this delete:
**
** ONEPASS_OFF: Two-pass approach - use a FIFO for rowids/PK values.
** ONEPASS_SINGLE: One-pass approach - at most one row deleted.
** ONEPASS_MULTI: One-pass approach - any number of rows may be deleted.
*/
pWInfo
=
sqlite3WhereBegin
(
pParse
,
pTabList
,
pWhere
,
0
,
0
,
wcf
,
iTabCur
+
1
);
if
(
pWInfo
==
0
) goto
delete_from_cleanup
;
eOnePass
=
sqlite3WhereOkOnePass
(
pWInfo
,
aiCurOnePass
);
assert
(
IsVirtual
(
pTab
)
==
0
||
eOnePass
!=
ONEPASS_MULTI
);
assert
(
IsVirtual
(
pTab
)
||
bComplex
||
eOnePass
!=
ONEPASS_OFF
);
if
(
eOnePass
!=
ONEPASS_SINGLE
)
sqlite3MultiWrite
(
pParse
);
/* Keep track of the number of rows to be deleted */
if
(
memCnt
){
sqlite3VdbeAddOp2
(
v
,
OP_AddImm
,
memCnt
,
1
);
}
/* Extract the rowid or primary key for the current row */
if
(
pPk
){
for
(
i
=
0
;
i
<
nPk
;
i
++
){
assert
(
pPk
->
aiColumn
[
i
]>=
0
);
sqlite3ExprCodeGetColumnOfTable
(
v
,
pTab
,
iTabCur
,
pPk
->
aiColumn
[
i
],
iPk
+
i
);
}
iKey
=
iPk
;
}
else
{
iKey
=
++
pParse
->
nMem
;
sqlite3ExprCodeGetColumnOfTable
(
v
,
pTab
,
iTabCur
,
-1
,
iKey
);
}
if
(
eOnePass
!=
ONEPASS_OFF
){
/* For ONEPASS, no need to store the rowid/primary-key. There is only
** one, so just keep it in its register(s) and fall through to the
** delete code. */
nKey
=
nPk
;
/* OP_Found will use an unpacked key */
aToOpen
=
sqlite3DbMallocRawNN
(
db
,
nIdx
+
2
);
if
(
aToOpen
==
0
){
sqlite3WhereEnd
(
pWInfo
);
goto
delete_from_cleanup
;
}
memset
(
aToOpen
,
1
,
nIdx
+
1
);
aToOpen
[
nIdx
+
1
]
=
0
;
if
(
aiCurOnePass
[
0
]>=
0
)
aToOpen
[
aiCurOnePass
[
0
]
-
iTabCur
]
=
0
;
if
(
aiCurOnePass
[
1
]>=
0
)
aToOpen
[
aiCurOnePass
[
1
]
-
iTabCur
]
=
0
;
if
(
addrEphOpen
)
sqlite3VdbeChangeToNoop
(
v
,
addrEphOpen
);
}
else
{
if
(
pPk
){
/* Add the PK key for this row to the temporary table */
iKey
=
++
pParse
->
nMem
;
nKey
=
0
;
/* Zero tells OP_Found to use a composite key */
sqlite3VdbeAddOp4
(
v
,
OP_MakeRecord
,
iPk
,
nPk
,
iKey
,
sqlite3IndexAffinityStr
(
pParse
->
db
,
pPk
),
nPk
);
sqlite3VdbeAddOp4Int
(
v
,
OP_IdxInsert
,
iEphCur
,
iKey
,
iPk
,
nPk
);
}
else
{
/* Add the rowid of the row to be deleted to the RowSet */
nKey
=
1
;
/* OP_DeferredSeek always uses a single rowid */
sqlite3VdbeAddOp2
(
v
,
OP_RowSetAdd
,
iRowSet
,
iKey
);
}
}
/* If this DELETE cannot use the ONEPASS strategy, this is the
** end of the WHERE loop */
if
(
eOnePass
!=
ONEPASS_OFF
){
addrBypass
=
sqlite3VdbeMakeLabel
(
pParse
);
}
else
{
sqlite3WhereEnd
(
pWInfo
);
}
/* Unless this is a view, open cursors for the table we are
** deleting from and all its indices. If this is a view, then the
** only effect this statement has is to fire the INSTEAD OF
** triggers.
*/
if
( !
isView
){
int
iAddrOnce
=
0
;
if
(
eOnePass
==
ONEPASS_MULTI
){
iAddrOnce
=
sqlite3VdbeAddOp0
(
v
,
OP_Once
);
VdbeCoverage
(
v
);
}
testcase
(
IsVirtual
(
pTab
) );
sqlite3OpenTableAndIndices
(
pParse
,
pTab
,
OP_OpenWrite
,
OPFLAG_FORDELETE
,
iTabCur
,
aToOpen
,
&
iDataCur
,
&
iIdxCur
);
assert
(
pPk
||
IsVirtual
(
pTab
)
||
iDataCur
==
iTabCur
);
assert
(
pPk
||
IsVirtual
(
pTab
)
||
iIdxCur
==
iDataCur
+
1
);
if
(
eOnePass
==
ONEPASS_MULTI
)
sqlite3VdbeJumpHere
(
v
,
iAddrOnce
);
}
/* Set up a loop over the rowids/primary-keys that were found in the
** where-clause loop above.
*/
if
(
eOnePass
!=
ONEPASS_OFF
){
assert
(
nKey
==
nPk
);
/* OP_Found will use an unpacked key */
if
( !
IsVirtual
(
pTab
)
&&
aToOpen
[
iDataCur
-
iTabCur
] ){
assert
(
pPk
!=
0
||
pTab
->
pSelect
!=
0
);
sqlite3VdbeAddOp4Int
(
v
,
OP_NotFound
,
iDataCur
,
addrBypass
,
iKey
,
nKey
);
VdbeCoverage
(
v
);
}
}
else
if
(
pPk
){
addrLoop
=
sqlite3VdbeAddOp1
(
v
,
OP_Rewind
,
iEphCur
);
VdbeCoverage
(
v
);
if
(
IsVirtual
(
pTab
) ){
sqlite3VdbeAddOp3
(
v
,
OP_Column
,
iEphCur
,
0
,
iKey
);
}
else
{
sqlite3VdbeAddOp2
(
v
,
OP_RowData
,
iEphCur
,
iKey
);
}
assert
(
nKey
==
0
);
/* OP_Found will use a composite key */
}
else
{
addrLoop
=
sqlite3VdbeAddOp3
(
v
,
OP_RowSetRead
,
iRowSet
,
0
,
iKey
);
VdbeCoverage
(
v
);
assert
(
nKey
==
1
);
}
/* Delete the row */
#ifndef
SQLITE_OMIT_VIRTUALTABLE
if
(
IsVirtual
(
pTab
) ){
const
char
*
pVTab
=
(
const
char
*
)
sqlite3GetVTable
(
db
,
pTab
);
sqlite3VtabMakeWritable
(
pParse
,
pTab
);
assert
(
eOnePass
==
ONEPASS_OFF
||
eOnePass
==
ONEPASS_SINGLE
);
sqlite3MayAbort
(
pParse
);
if
(
eOnePass
==
ONEPASS_SINGLE
){
sqlite3VdbeAddOp1
(
v
,
OP_Close
,
iTabCur
);
if
(
sqlite3IsToplevel
(
pParse
) ){
pParse
->
isMultiWrite
=
0
;
}
}
sqlite3VdbeAddOp4
(
v
,
OP_VUpdate
,
0
,
1
,
iKey
,
pVTab
,
P4_VTAB
);
sqlite3VdbeChangeP5
(
v
,
OE_Abort
);
}
else
#endif
{
int
count
=
(
pParse
->
nested
==
0
);
/* True to count changes */
sqlite3GenerateRowDelete
(
pParse
,
pTab
,
pTrigger
,
iDataCur
,
iIdxCur
,
iKey
,
nKey
,
count
,
OE_Default
,
eOnePass
,
aiCurOnePass
[
1
]);
}
/* End of the loop over all rowids/primary-keys. */
if
(
eOnePass
!=
ONEPASS_OFF
){
sqlite3VdbeResolveLabel
(
v
,
addrBypass
);
sqlite3WhereEnd
(
pWInfo
);
}
else
if
(
pPk
){
sqlite3VdbeAddOp2
(
v
,
OP_Next
,
iEphCur
,
addrLoop
+
1
);
VdbeCoverage
(
v
);
sqlite3VdbeJumpHere
(
v
,
addrLoop
);
}
else
{
sqlite3VdbeGoto
(
v
,
addrLoop
);
sqlite3VdbeJumpHere
(
v
,
addrLoop
);
}
}
/* End non-truncate path */
/* Update the sqlite_sequence table by storing the content of the
** maximum rowid counter values recorded while inserting into
** autoincrement tables.
*/
if
(
pParse
->
nested
==
0
&&
pParse
->
pTriggerTab
==
0
){
sqlite3AutoincrementEnd
(
pParse
);
}
/* Return the number of rows that were deleted. If this routine is
** generating code because of a call to sqlite3NestedParse(), do not
** invoke the callback function.
*/
if
(
memCnt
){
sqlite3VdbeAddOp2
(
v
,
OP_ResultRow
,
memCnt
,
1
);
sqlite3VdbeSetNumCols
(
v
,
1
);
sqlite3VdbeSetColName
(
v
,
0
,
COLNAME_NAME
,
"rows deleted"
,
SQLITE_STATIC
);
}
delete_from_cleanup
:
sqlite3AuthContextPop
(
&
sContext
);
sqlite3SrcListDelete
(
db
,
pTabList
);
sqlite3ExprDelete
(
db
,
pWhere
);
#if
defined(
SQLITE_ENABLE_UPDATE_DELETE_LIMIT
)
sqlite3ExprListDelete
(
db
,
pOrderBy
);
sqlite3ExprDelete
(
db
,
pLimit
);
#endif
sqlite3DbFree
(
db
,
aToOpen
);
return
;
}
/* Make sure "isView" and other macros defined above are undefined. Otherwise
** they may interfere with compilation of other functions in this file
** (or in another file, if this file becomes part of the amalgamation). */
#ifdef
isView
#undef
isView
#endif
#ifdef
pTrigger
#undef
pTrigger
#endif
/*
** This routine generates VDBE code that causes a single row of a
** single table to be deleted. Both the original table entry and
** all indices are removed.
**
** Preconditions:
**
** 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.)
**
** 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. If nPk==0 that means
** that a search record formed from OP_MakeRecord is contained in the
** single memory location iPk.
**
** eMode:
** Parameter eMode may be passed either ONEPASS_OFF (0), ONEPASS_SINGLE, or
** ONEPASS_MULTI. If eMode is not ONEPASS_OFF, then the cursor
** iDataCur already points to the row to delete. If eMode is ONEPASS_OFF
** then this function must seek iDataCur to the entry identified by iPk
** and nPk before reading from it.
**
** If eMode is ONEPASS_MULTI, then this call is being made as part
** of a ONEPASS delete that affects multiple rows. In this case, if
** iIdxNoSeek is a valid cursor number (>=0) and is not the same as
** iDataCur, then its position should be preserved following the delete
** operation. Or, if iIdxNoSeek is not a valid cursor number, the
** position of iDataCur should be preserved instead.
**
** iIdxNoSeek:
** If iIdxNoSeek is a valid cursor number (>=0) not equal to iDataCur,
** then it identifies an index cursor (from within array of cursors
** starting at iIdxCur) that already points to the index entry to be deleted.
** Except, this optimization is disabled if there are BEFORE triggers since
** the trigger body might have moved the cursor.
*/
void
sqlite3GenerateRowDelete
(
Parse
*
pParse
,
/* Parsing context */
Table
*
pTab
,
/* Table containing the row to be deleted */
Trigger
*
pTrigger
,
/* List of triggers to (potentially) fire */
int
iDataCur
,
/* Cursor from which column data is extracted */
int
iIdxCur
,
/* First index cursor */
int
iPk
,
/* First memory cell containing the PRIMARY KEY */
i16
nPk
,
/* Number of PRIMARY KEY memory cells */
u8
count
,
/* If non-zero, increment the row change counter */
u8
onconf
,
/* Default ON CONFLICT policy for triggers */
u8
eMode
,
/* ONEPASS_OFF, _SINGLE, or _MULTI. See above */
int
iIdxNoSeek
/* Cursor number of cursor that does not need seeking */
){
Vdbe
*
v
=
pParse
->
pVdbe
;
/* Vdbe */
int
iOld
=
0
;
/* First register in OLD.* array */
int
iLabel
;
/* Label resolved to end of generated code */
u8
opSeek
;
/* Seek opcode */
/* Vdbe is guaranteed to have been allocated by this stage. */
assert
(
v
);
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
** (this can happen if a trigger program has already deleted it), do
** not attempt to delete it or fire any DELETE triggers. */
iLabel
=
sqlite3VdbeMakeLabel
(
pParse
);
opSeek
=
HasRowid
(
pTab
) ?
OP_NotExists
:
OP_NotFound
;
if
(
eMode
==
ONEPASS_OFF
){
sqlite3VdbeAddOp4Int
(
v
,
opSeek
,
iDataCur
,
iLabel
,
iPk
,
nPk
);
VdbeCoverageIf
(
v
,
opSeek
==
OP_NotExists
);
VdbeCoverageIf
(
v
,
opSeek
==
OP_NotFound
);
}
/* If there are any triggers to fire, allocate a range of registers to
** use for the old.* references in the triggers. */
if
(
sqlite3FkRequired
(
pParse
,
pTab
,
0
,
0
)
||
pTrigger
){
u32
mask
;
/* Mask of OLD.* columns in use */
int
iCol
;
/* Iterator used while populating OLD.* */
int
addrStart
;
/* Start of BEFORE trigger programs */
/* TODO: Could use temporary registers here. Also could attempt to
** avoid copying the contents of the rowid register. */
mask
=
sqlite3TriggerColmask
(
pParse
,
pTrigger
,
0
,
0
,
TRIGGER_BEFORE
|
TRIGGER_AFTER
,
pTab
,
onconf
);
mask
|=
sqlite3FkOldmask
(
pParse
,
pTab
);
iOld
=
pParse
->
nMem
+
1
;
pParse
->
nMem
+=
(
1
+
pTab
->
nCol
);
/* Populate the OLD.* pseudo-table register array. These values will be
** used by any BEFORE and AFTER triggers that exist. */
sqlite3VdbeAddOp2
(
v
,
OP_Copy
,
iPk
,
iOld
);
for
(
iCol
=
0
;
iCol
<
pTab
->
nCol
;
iCol
++
){
testcase
(
mask
!=
0xffffffff
&&
iCol
==
31
);
testcase
(
mask
!=
0xffffffff
&&
iCol
==
32
);
if
(
mask
==
0xffffffff
||
(
iCol
<=
31
&&
(
mask
&
MASKBIT32
(
iCol
))
!=
0
) ){
int
kk
=
sqlite3TableColumnToStorage
(
pTab
,
iCol
);
sqlite3ExprCodeGetColumnOfTable
(
v
,
pTab
,
iDataCur
,
iCol
,
iOld
+
kk
+
1
);
}
}
/* Invoke BEFORE DELETE trigger programs. */
addrStart
=
sqlite3VdbeCurrentAddr
(
v
);
sqlite3CodeRowTrigger
(
pParse
,
pTrigger
,
TK_DELETE
,
0
,
TRIGGER_BEFORE
,
pTab
,
iOld
,
onconf
,
iLabel
);
/* If any BEFORE triggers were coded, then seek the cursor to the
** row to be deleted again. It may be that the BEFORE triggers moved
** the cursor or already deleted the row that the cursor was
** pointing to.
**
** Also disable the iIdxNoSeek optimization since the BEFORE trigger
** may have moved that cursor.
*/
if
(
addrStart
<
sqlite3VdbeCurrentAddr
(
v
) ){
sqlite3VdbeAddOp4Int
(
v
,
opSeek
,
iDataCur
,
iLabel
,
iPk
,
nPk
);
VdbeCoverageIf
(
v
,
opSeek
==
OP_NotExists
);
VdbeCoverageIf
(
v
,
opSeek
==
OP_NotFound
);
testcase
(
iIdxNoSeek
>=
0
);
iIdxNoSeek
=
-1
;
}
/* Do FK processing. This call checks that any FK constraints that
** refer to this table (i.e. constraints attached to other tables)
** are not violated by deleting this row. */
sqlite3FkCheck
(
pParse
,
pTab
,
iOld
,
0
,
0
,
0
);
}
/* Delete the index and table entries. Skip this step if pTab is really
** a view (in which case the only effect of the DELETE statement is to
** fire the INSTEAD OF triggers).
**
** If variable 'count' is non-zero, then this OP_Delete instruction should
** invoke the update-hook. The pre-update-hook, on the other hand should
** be invoked unless table pTab is a system table. The difference is that
** the update-hook is not invoked for rows removed by REPLACE, but the
** pre-update-hook is.
*/
if
(
pTab
->
pSelect
==
0
){
u8
p5
=
0
;
sqlite3GenerateRowIndexDelete
(
pParse
,
pTab
,
iDataCur
,
iIdxCur
,
0
,
iIdxNoSeek
);
sqlite3VdbeAddOp2
(
v
,
OP_Delete
,
iDataCur
, (
count
?
OPFLAG_NCHANGE
:
0
));
if
(
pParse
->
nested
==
0
||
0
==
sqlite3_stricmp
(
pTab
->
zName
,
"sqlite_stat1"
) ){
sqlite3VdbeAppendP4
(
v
, (
char
*
)
pTab
,
P4_TABLE
);
}
if
(
eMode
!=
ONEPASS_OFF
){
sqlite3VdbeChangeP5
(
v
,
OPFLAG_AUXDELETE
);
}
if
(
iIdxNoSeek
>=
0
&&
iIdxNoSeek
!=
iDataCur
){
sqlite3VdbeAddOp1
(
v
,
OP_Delete
,
iIdxNoSeek
);
}
if
(
eMode
==
ONEPASS_MULTI
)
p5
|=
OPFLAG_SAVEPOSITION
;
sqlite3VdbeChangeP5
(
v
,
p5
);
}
/* Do any ON CASCADE, SET NULL or SET DEFAULT operations required to
** handle rows (possibly in other tables) that refer via a foreign key
** to the row just deleted. */
sqlite3FkActions
(
pParse
,
pTab
,
0
,
iOld
,
0
,
0
);
/* Invoke AFTER DELETE trigger programs. */
sqlite3CodeRowTrigger
(
pParse
,
pTrigger
,
TK_DELETE
,
0
,
TRIGGER_AFTER
,
pTab
,
iOld
,
onconf
,
iLabel
);
/* Jump here if the row had already been deleted before any BEFORE
** trigger programs were invoked. Or if a trigger program throws a
** RAISE(IGNORE) exception. */
sqlite3VdbeResolveLabel
(
v
,
iLabel
);
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, pTab
**
** Preconditions:
**
** 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.)
**
** 2. Read/write cursors for all indices of pTab must be open as
** cursor number iIdxCur+i for the i-th index. (The pTab->pIndex
** index is the 0-th index.)
**
** 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 */
Table
*
pTab
,
/* Table containing the row to be deleted */
int
iDataCur
,
/* Cursor of table holding data. */
int
iIdxCur
,
/* First index cursor */
int
*
aRegIdx
,
/* Only delete if aRegIdx!=0 && aRegIdx[i]>0 */
int
iIdxNoSeek
/* Do not delete from this cursor */
){
int
i
;
/* Index loop counter */
int
r1
=
-1
;
/* Register holding an index key */
int
iPartIdxLabel
;
/* Jump destination for skipping partial index entries */
Index
*
pIdx
;
/* Current index */
Index
*
pPrior
=
0
;
/* Prior 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
;
if
(
iIdxCur
+
i
==
iIdxNoSeek
)
continue
;
VdbeModuleComment
((
v
,
"GenRowIdxDel for %s"
,
pIdx
->
zName
));
r1
=
sqlite3GenerateIndexKey
(
pParse
,
pIdx
,
iDataCur
,
0
,
1
,
&
iPartIdxLabel
,
pPrior
,
r1
);
sqlite3VdbeAddOp3
(
v
,
OP_IdxDelete
,
iIdxCur
+
i
,
r1
,
pIdx
->
uniqNotNull
?
pIdx
->
nKeyCol
:
pIdx
->
nColumn
);
sqlite3ResolvePartIdxLabel
(
pParse
,
iPartIdxLabel
);
pPrior
=
pIdx
;
}
}
/*
** Generate code that will assemble an index key and stores it in register
** regOut. The key with be for index pIdx which is an index on pTab.
** iCur is the index of a cursor open on the pTab table and pointing to
** the entry that needs indexing. If pTab is a WITHOUT ROWID table, then
** iCur must be the cursor of the PRIMARY KEY index.
**
** Return a register number which is the first in a block of
** registers that holds the elements of the index key. The
** block of registers has already been deallocated by the time
** this routine returns.
**
** If *piPartIdxLabel is not NULL, fill it in with a label and jump
** to that label if pIdx is a partial index that should be skipped.
** The label should be resolved using sqlite3ResolvePartIdxLabel().
** A partial index should be skipped if its WHERE clause evaluates
** to false or null. If pIdx is not a partial index, *piPartIdxLabel
** will be set to zero which is an empty label that is ignored by
** sqlite3ResolvePartIdxLabel().
**
** The pPrior and regPrior parameters are used to implement a cache to
** avoid unnecessary register loads. If pPrior is not NULL, then it is
** a pointer to a different index for which an index key has just been
** computed into register regPrior. If the current pIdx index is generating
** its key into the same sequence of registers and if pPrior and pIdx share
** a column in common, then the register corresponding to that column already
** holds the correct value and the loading of that register is skipped.
** This optimization is helpful when doing a DELETE or an INTEGRITY_CHECK
** on a table with multiple indices, and especially with the ROWID or
** PRIMARY KEY columns of the index.
*/
int
sqlite3GenerateIndexKey
(
Parse
*
pParse
,
/* Parsing context */
Index
*
pIdx
,
/* The index for which to generate a key */
int
iDataCur
,
/* Cursor number from which to take column data */
int
regOut
,
/* Put the new key into this register if not 0 */
int
prefixOnly
,
/* Compute only a unique prefix of the key */
int
*
piPartIdxLabel
,
/* OUT: Jump to this label to skip partial index */
Index
*
pPrior
,
/* Previously generated index key */
int
regPrior
/* Register holding previous generated key */
){
Vdbe
*
v
=
pParse
->
pVdbe
;
int
j
;
int
regBase
;
int
nCol
;
if
(
piPartIdxLabel
){
if
(
pIdx
->
pPartIdxWhere
){
*
piPartIdxLabel
=
sqlite3VdbeMakeLabel
(
pParse
);
pParse
->
iSelfTab
=
iDataCur
+
1
;
sqlite3ExprIfFalseDup
(
pParse
,
pIdx
->
pPartIdxWhere
,
*
piPartIdxLabel
,
SQLITE_JUMPIFNULL
);
pParse
->
iSelfTab
=
0
;
pPrior
=
0
;
/* Ticket a9efb42811fa41ee 2019-11-02;
** pPartIdxWhere may have corrupted regPrior registers */
}
else
{
*
piPartIdxLabel
=
0
;
}
}
nCol
=
(
prefixOnly
&&
pIdx
->
uniqNotNull
) ?
pIdx
->
nKeyCol
:
pIdx
->
nColumn
;
regBase
=
sqlite3GetTempRange
(
pParse
,
nCol
);
if
(
pPrior
&&
(
regBase
!=
regPrior
||
pPrior
->
pPartIdxWhere
) )
pPrior
=
0
;
for
(
j
=
0
;
j
<
nCol
;
j
++
){
if
(
pPrior
&&
pPrior
->
aiColumn
[
j
]
==
pIdx
->
aiColumn
[
j
]
&&
pPrior
->
aiColumn
[
j
]
!=
XN_EXPR
){
/* This column was already computed by the previous index */
continue
;
}
sqlite3ExprCodeLoadIndexColumn
(
pParse
,
pIdx
,
iDataCur
,
j
,
regBase
+
j
);
/* If the column affinity is REAL but the number is an integer, then it
** might be stored in the table as an integer (using a compact
** representation) then converted to REAL by an OP_RealAffinity opcode.
** But we are getting ready to store this value back into an index, where
** it should be converted by to INTEGER again. So omit the OP_RealAffinity
** opcode if it is present */
sqlite3VdbeDeletePriorOpcode
(
v
,
OP_RealAffinity
);
}
if
(
regOut
){
sqlite3VdbeAddOp3
(
v
,
OP_MakeRecord
,
regBase
,
nCol
,
regOut
);
if
(
pIdx
->
pTable
->
pSelect
){
const
char
*
zAff
=
sqlite3IndexAffinityStr
(
pParse
->
db
,
pIdx
);
sqlite3VdbeChangeP4
(
v
,
-1
,
zAff
,
P4_TRANSIENT
);
}
}
sqlite3ReleaseTempRange
(
pParse
,
regBase
,
nCol
);
return
regBase
;
}
/*
** If a prior call to sqlite3GenerateIndexKey() generated a jump-over label
** because it was a partial index, then this routine should be called to
** resolve that label.
*/
void
sqlite3ResolvePartIdxLabel
(
Parse
*
pParse
,
int
iLabel
){
if
(
iLabel
){
sqlite3VdbeResolveLabel
(
pParse
->
pVdbe
,
iLabel
);
}
}
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