static void UpdateVirtualTable(Parse parse, SrcList src, Table table, ExprList changes, Expr rowid, int[] xrefs, Expr where_, int onError)
{
int i;
Context ctx = parse.Ctx; // Database connection
VTable vtable = VTable.GetVTable(ctx, table);
SelectDest dest = new SelectDest();
// Construct the SELECT statement that will find the new values for all updated rows.
ExprList list = ExprList.Append(parse, 0, Expr.Expr(ctx, TK.ID, "_rowid_")); // The result set of the SELECT statement
if (rowid != null)
{
list = ExprList.Append(parse, list, Expr.Dup(ctx, rowid, 0));
}
Debug.Assert(table.PKey < 0);
for (i = 0; i < table.Cols.length; i++)
{
Expr expr = (xrefs[i] >= 0 ? Expr.Dup(ctx, changes.Ids[xrefs[i]].Expr, 0) : Expr.Expr(ctx, TK.ID, table.Cols[i].Name)); // Temporary expression
list = ExprList.Append(parse, list, expr);
}
Select select = Select.New(parse, list, src, where_, null, null, null, 0, null, null); // The SELECT statement
// Create the ephemeral table into which the update results will be stored.
Vdbe v = parse.V; // Virtual machine under construction
Debug.Assert(v != null);
int ephemTab = parse.Tabs++; // Table holding the result of the SELECT
v.AddOp2(OP.OpenEphemeral, ephemTab, table.Cols.length + 1 + (rowid != null ? 1 : 0));
v.ChangeP5(BTREE_UNORDERED);
// fill the ephemeral table
Select.DestInit(dest, SRT.Table, ephemTab);
Select.Select(parse, select, ref dest);
// Generate code to scan the ephemeral table and call VUpdate.
int regId = ++parse.Mems;// First register in set passed to OP_VUpdate
parse.Mems += table.Cols.length + 1;
int addr = v.AddOp2(OP.Rewind, ephemTab, 0); // Address of top of loop
v.AddOp3(OP.Column, ephemTab, 0, regId);
v.AddOp3(OP.Column, ephemTab, (rowid != null ? 1 : 0), regId + 1);
for (i = 0; i < table.nCol; i++)
{
v.AddOp3(OP.Column, ephemTab, i + 1 + (rowid != null ? 1 : 0), regId + 2 + i);
}
sqlite3VtabMakeWritable(parse, table);
v.AddOp4(OP_VUpdate, 0, table.Cols.length + 2, regId, vtable, P4_VTAB);
v.ChangeP5((byte)(onError == OE_Default ? OE_Abort : onError));
parse.MayAbort();
v.AddOp2(OP.Next, ephemTab, addr + 1);
v.JumpHere(addr);
v.AddOp2(OP.Close, ephemTab, 0);
// Cleanup
Select.Delete(ctx, ref select);
}
static Trigger FKActionTrigger(Parse parse, Table table, FKey fkey, ExprList changes)
{
Context ctx = parse.Ctx; // Database handle
int actionId = (changes != null ? 1 : 0); // 1 for UPDATE, 0 for DELETE
OE action = fkey.Actions[actionId]; // One of OE_None, OE_Cascade etc.
Trigger trigger = fkey.Triggers[actionId]; // Trigger definition to return
if (action != OE.None && trigger == null)
{
Index index = null; // Parent key index for this FK
int[] cols = null; // child table cols . parent key cols
if (LocateFkeyIndex(parse, table, fkey, out index, out cols) != 0)
{
return(null);
}
Debug.Assert(cols != null || fkey.Cols.length == 1);
Expr where_ = null; // WHERE clause of trigger step
Expr when = null; // WHEN clause for the trigger
ExprList list = null; // Changes list if ON UPDATE CASCADE
for (int i = 0; i < fkey.Cols.length; i++)
{
Token oldToken = new Token("old", 3); // Literal "old" token
Token newToken = new Token("new", 3); // Literal "new" token
int fromColId = (cols != null ? cols[i] : fkey.Cols[0].From); // Idx of column in child table
Debug.Assert(fromColId >= 0);
Token fromCol = new Token(); // Name of column in child table
Token toCol = new Token(); // Name of column in parent table
toCol.data = (index != null ? table.Cols[index.Columns[i]].Name : "oid");
fromCol.data = fkey.From.Cols[fromColId].Name;
toCol.length = (uint)toCol.data.Length;
fromCol.length = (uint)fromCol.data.Length;
// Create the expression "OLD.zToCol = zFromCol". It is important that the "OLD.zToCol" term is on the LHS of the = operator, so
// that the affinity and collation sequence associated with the parent table are used for the comparison.
Expr eq = Expr.PExpr(parse, TK.EQ,
Expr.PExpr(parse, TK.DOT,
Expr.PExpr(parse, TK.ID, null, null, oldToken),
Expr.PExpr(parse, TK.ID, null, null, toCol)
, 0),
Expr.PExpr(parse, TK.ID, null, null, fromCol)
, 0); // tFromCol = OLD.tToCol
where_ = Expr.And(ctx, where_, eq);
// For ON UPDATE, construct the next term of the WHEN clause. The final WHEN clause will be like this:
//
// WHEN NOT(old.col1 IS new.col1 AND ... AND old.colN IS new.colN)
if (changes != null)
{
eq = Expr.PExpr(parse, TK.IS,
Expr.PExpr(parse, TK.DOT,
Expr.PExpr(parse, TK.ID, null, null, oldToken),
Expr.PExpr(parse, TK.ID, null, null, toCol),
0),
Expr.PExpr(parse, TK.DOT,
Expr.PExpr(parse, TK.ID, null, null, newToken),
Expr.PExpr(parse, TK.ID, null, null, toCol),
0),
0);
when = Expr.And(ctx, when, eq);
}
if (action != OE.Restrict && (action != OE.Cascade || changes != null))
{
Expr newExpr;
if (action == OE.Cascade)
{
newExpr = Expr.PExpr(parse, TK.DOT,
Expr.PExpr(parse, TK.ID, null, null, newToken),
Expr.PExpr(parse, TK.ID, null, null, toCol)
, 0);
}
else if (action == OE.SetDflt)
{
Expr dfltExpr = fkey.From.Cols[fromColId].Dflt;
if (dfltExpr != null)
{
newExpr = Expr.Dup(ctx, dfltExpr, 0);
}
else
{
newExpr = Expr.PExpr(parse, TK.NULL, 0, 0, 0);
}
}
else
{
newExpr = Expr.PExpr(parse, TK.NULL, 0, 0, 0);
}
list = Expr.ListAppend(parse, list, newExpr);
Expr.ListSetName(parse, list, fromCol, 0);
}
}
C._tagfree(ctx, ref cols);
string fromName = fkey.From.Name; // Name of child table
int fromNameLength = fromName.Length; // Length in bytes of zFrom
Select select = null; // If RESTRICT, "SELECT RAISE(...)"
if (action == OE.Restrict)
{
Token from = new Token();
from.data = fromName;
from.length = fromNameLength;
Expr raise = Expr.Expr(ctx, TK.RAISE, "foreign key constraint failed");
if (raise != null)
{
raise.Affinity = OE.Abort;
}
select = Select.New(parse,
Expr.ListAppend(parse, 0, raise),
SrcListAppend(ctx, 0, from, null),
where_,
null, null, null, 0, null, null);
where_ = null;
}
// Disable lookaside memory allocation
bool enableLookaside = ctx.Lookaside.Enabled; // Copy of ctx->lookaside.bEnabled
ctx.Lookaside.Enabled = false;
trigger = new Trigger();
//: trigger = (Trigger *)_tagalloc(ctx,
//: sizeof(Trigger) + // Trigger
//: sizeof(TriggerStep) + // Single step in trigger program
//: fromNameLength + 1 // Space for pStep->target.z
//: , true);
TriggerStep step = null; // First (only) step of trigger program
if (trigger != null)
{
step = trigger.StepList = new TriggerStep(); //: (TriggerStep)trigger[1];
step.Target.data = fromName; //: (char *)&step[1];
step.Target.length = fromNameLength;
//: _memcpy((const char *)step->Target.data, fromName, fromNameLength);
step.Where = Expr.Dup(ctx, where_, EXPRDUP_REDUCE);
step.ExprList = Expr.ListDup(ctx, list, EXPRDUP_REDUCE);
step.Select = Select.Dup(ctx, select, EXPRDUP_REDUCE);
if (when != null)
{
when = Expr.PExpr(parse, TK.NOT, when, 0, 0);
trigger.When = Expr.Dup(ctx, when, EXPRDUP_REDUCE);
}
}
// Re-enable the lookaside buffer, if it was disabled earlier.
ctx.Lookaside.Enabled = enableLookaside;
Expr.Delete(ctx, ref where_);
Expr.Delete(ctx, ref when);
Expr.ListDelete(ctx, ref list);
Select.Delete(ctx, ref select);
if (ctx.MallocFailed)
{
FKTriggerDelete(ctx, trigger);
return(null);
}
switch (action)
{
case OE.Restrict:
step.OP = TK.SELECT;
break;
case OE.Cascade:
if (changes == null)
{
step.OP = TK.DELETE;
break;
}
goto default;
default:
step.OP = TK.UPDATE;
break;
}
step.Trigger = trigger;
trigger.Schema = table.Schema;
trigger.TabSchema = table.Schema;
fkey.Triggers[actionId] = trigger;
trigger.OP = (TK)(changes != null ? TK.UPDATE : TK.DELETE);
}
return(trigger);
}
static void FKScanChildren(Parse parse, SrcList src, Table table, Index index, FKey fkey, int[] cols, int regDataId, int incr)
{
Context ctx = parse.Ctx; // Database handle
Vdbe v = parse.GetVdbe();
Expr where_ = null; // WHERE clause to scan with
Debug.Assert(index == null || index.Table == table);
int fkIfZero = 0; // Address of OP_FkIfZero
if (incr < 0)
{
fkIfZero = v.AddOp2(OP.FkIfZero, fkey.IsDeferred, 0);
}
// Create an Expr object representing an SQL expression like:
//
// <parent-key1> = <child-key1> AND <parent-key2> = <child-key2> ...
//
// The collation sequence used for the comparison should be that of the parent key columns. The affinity of the parent key column should
// be applied to each child key value before the comparison takes place.
for (int i = 0; i < fkey.Cols.length; i++)
{
int col; // Index of column in child table
Expr left = Expr.Expr(ctx, TK.REGISTER, null); // Value from parent table row
if (left != null)
{
// Set the collation sequence and affinity of the LHS of each TK_EQ expression to the parent key column defaults.
if (index != null)
{
col = index.Columns[i];
Column colObj = table.Cols[col];
if (table.PKey == col)
{
col = -1;
}
left.TableId = regDataId + col + 1;
left.Aff = colObj.Affinity;
string collName = colObj.Coll;
if (collName == null)
{
collName = ctx.DefaultColl.Name;
}
left = Expr.AddCollateString(parse, left, collName);
}
else
{
left.TableId = regDataId;
left.Aff = AFF.INTEGER;
}
}
col = (cols != null ? cols[i] : fkey.Cols[0].From);
Debug.Assert(col >= 0);
string colName = fkey.From.Cols[col].Name; // Name of column in child table
Expr right = Expr.Expr(ctx, TK.ID, colName); // Column ref to child table
Expr eq = Expr.PExpr(parse, TK.EQ, left, right, 0); // Expression (pLeft = pRight)
where_ = Expr.And(ctx, where_, eq);
}
// If the child table is the same as the parent table, and this scan is taking place as part of a DELETE operation (operation D.2), omit the
// row being deleted from the scan by adding ($rowid != rowid) to the WHERE clause, where $rowid is the rowid of the row being deleted.
if (table == fkey.From && incr > 0)
{
Expr left = Expr.Expr(ctx, TK.REGISTER, null); // Value from parent table row
Expr right = Expr.Expr(ctx, TK.COLUMN, null); // Column ref to child table
if (left != null && right != null)
{
left.TableId = regDataId;
left.Aff = AFF.INTEGER;
right.TableId = src.Ids[0].Cursor;
right.ColumnId = -1;
}
Expr eq = Expr.PExpr(parse, TK.NE, left, right, 0); // Expression (pLeft = pRight)
where_ = Expr.And(ctx, where_, eq);
}
// Resolve the references in the WHERE clause.
NameContext nameContext; // Context used to resolve WHERE clause
nameContext = new NameContext(); // memset( &sNameContext, 0, sizeof( NameContext ) );
nameContext.SrcList = src;
nameContext.Parse = parse;
ResolveExprNames(nameContext, ref where_);
// Create VDBE to loop through the entries in src that match the WHERE clause. If the constraint is not deferred, throw an exception for
// each row found. Otherwise, for deferred constraints, increment the deferred constraint counter by incr for each row selected.
ExprList dummy = null;
WhereInfo whereInfo = Where.Begin(parse, src, where_, ref dummy, 0); // Context used by sqlite3WhereXXX()
if (incr > 0 && !fkey.IsDeferred)
{
E.Parse_Toplevel(parse).MayAbort = true;
}
v.AddOp2(OP.FkCounter, fkey.IsDeferred, incr);
if (whereInfo != null)
{
Where.End(whereInfo);
}
// Clean up the WHERE clause constructed above.
Expr.Delete(ctx, ref where_);
if (fkIfZero != 0)
{
v.JumpHere(fkIfZero);
}
}
