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);
}
public static bool IsReadOnly(Parse parse, Table table, bool viewOk)
{
// A table is not writable under the following circumstances:
// 1) It is a virtual table and no implementation of the xUpdate method has been provided, or
// 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.
// In either case leave an error message in pParse and return non-zero.
if ((E.IsVirtual(table) && VTable.GetVTable(parse.Ctx, table).Module.IModule.Update == null) ||
((table.TabFlags & TF.Readonly) != 0 && (parse.Ctx.Flags & Context.FLAG.WriteSchema) == 0 && parse.Nested == 0))
{
parse.ErrorMsg("table %s may not be modified", table.Name);
return true;
}
#if !OMIT_VIEW
if (!viewOk && table.Select != null)
{
parse.ErrorMsg("cannot modify %s because it is a view", table.Name);
return true;
}
#endif
return false;
}
public static void RenameTable(Parse parse, SrcList src, Token name)
{
Context ctx = parse.Ctx; // Database connection
Context.FLAG savedDbFlags = ctx.Flags; // Saved value of db->flags
//if (C._NEVER(ctx.MallocFailed)) goto exit_rename_table;
Debug.Assert(src.Srcs == 1);
Debug.Assert(Btree.HoldsAllMutexes(ctx));
Table table = parse.LocateTableItem(false, src.Ids[0]); // Table being renamed
if (table == null)
{
goto exit_rename_table;
}
int db = Prepare.SchemaToIndex(ctx, table.Schema); // Database that contains the table
string dbName = ctx.DBs[db].Name; // Name of database iDb
ctx.Flags |= Context.FLAG.PreferBuiltin;
// Get a NULL terminated version of the new table name.
string nameAsString = Parse.NameFromToken(ctx, name); // NULL-terminated version of pName
if (nameAsString == null)
{
goto exit_rename_table;
}
// Check that a table or index named 'zName' does not already exist in database iDb. If so, this is an error.
if (Parse.FindTable(ctx, nameAsString, dbName) != null || Parse.FindIndex(ctx, nameAsString, dbName) != null)
{
parse.ErrorMsg("there is already another table or index with this name: %s", nameAsString);
goto exit_rename_table;
}
// Make sure it is not a system table being altered, or a reserved name that the table is being renamed to.
if (IsSystemTable(parse, table.Name) || parse->CheckObjectName(nameAsString) != RC.OK)
{
goto exit_rename_table;
}
#if !OMIT_VIEW
if (table.Select != null)
{
parse.ErrorMsg("view %s may not be altered", table.Name);
goto exit_rename_table;
}
#endif
#if !OMIT_AUTHORIZATION
// Invoke the authorization callback.
if (Auth.Check(parse, AUTH.ALTER_TABLE, dbName, table.Name, null))
{
goto exit_rename_table;
}
#endif
VTable vtable = null; // Non-zero if this is a v-tab with an xRename()
#if !OMIT_VIRTUALTABLE
if (parse->ViewGetColumnNames(table) != 0)
{
goto exit_rename_table;
}
if (E.IsVirtual(table))
{
vtable = VTable.GetVTable(ctx, table);
if (vtable.IVTable.IModule.Rename == null)
{
vtable = null;
}
}
#endif
// Begin a transaction and code the VerifyCookie for database iDb. Then modify the schema cookie (since the ALTER TABLE modifies the
// schema). Open a statement transaction if the table is a virtual table.
Vdbe v = parse.GetVdbe();
if (v == null)
{
goto exit_rename_table;
}
parse.BeginWriteOperation((vtable != null ? 1 : 0), db);
parse.ChangeCookie(db);
// If this is a virtual table, invoke the xRename() function if one is defined. The xRename() callback will modify the names
// of any resources used by the v-table implementation (including other SQLite tables) that are identified by the name of the virtual table.
#if !OMIT_VIRTUALTABLE
if (vtable != null)
{
int i = ++parse.Mems;
v.AddOp4(OP.String8, 0, i, 0, nameAsString, 0);
v.AddOp4(OP.VRename, i, 0, 0, vtable, Vdbe.P4T.VTAB);
parse.MayAbort();
}
#endif
// figure out how many UTF-8 characters are in zName
string tableName = table.Name; // Original name of the table
int tableNameLength = C._utf8charlength(tableName, -1); // Number of UTF-8 characters in zTabName
#if !OMIT_TRIGGER
string where_ = string.Empty; // Where clause to locate temp triggers
#endif
#if !OMIT_FOREIGN_KEY && !OMIT_TRIGGER
if ((ctx.Flags & Context.FLAG.ForeignKeys) != 0)
{
// If foreign-key support is enabled, rewrite the CREATE TABLE statements corresponding to all child tables of foreign key constraints
// for which the renamed table is the parent table.
if ((where_ = WhereForeignKeys(parse, table)) != null)
{
parse.NestedParse(
"UPDATE \"%w\".%s SET " +
"sql = sqlite_rename_parent(sql, %Q, %Q) " +
"WHERE %s;", dbName, E.SCHEMA_TABLE(db), tableName, nameAsString, where_);
C._tagfree(ctx, ref where_);
}
}
#endif
// Modify the sqlite_master table to use the new table name.
parse.NestedParse(
"UPDATE %Q.%s SET " +
#if OMIT_TRIGGER
"sql = sqlite_rename_table(sql, %Q), " +
#else
"sql = CASE " +
"WHEN type = 'trigger' THEN sqlite_rename_trigger(sql, %Q)" +
"ELSE sqlite_rename_table(sql, %Q) END, " +
#endif
"tbl_name = %Q, " +
"name = CASE " +
"WHEN type='table' THEN %Q " +
"WHEN name LIKE 'sqlite_autoindex%%' AND type='index' THEN " +
"'sqlite_autoindex_' || %Q || substr(name,%d+18) " +
"ELSE name END " +
"WHERE tbl_name=%Q AND " +
"(type='table' OR type='index' OR type='trigger');",
dbName, SCHEMA_TABLE(db), nameAsString, nameAsString, nameAsString,
#if !OMIT_TRIGGER
nameAsString,
#endif
nameAsString, tableNameLength, tableName);
#if !OMIT_AUTOINCREMENT
// If the sqlite_sequence table exists in this database, then update it with the new table name.
if (Parse.FindTable(ctx, "sqlite_sequence", dbName) != null)
{
parse.NestedParse(
"UPDATE \"%w\".sqlite_sequence set name = %Q WHERE name = %Q",
dbName, nameAsString, table.Name);
}
#endif
#if !OMIT_TRIGGER
// If there are TEMP triggers on this table, modify the sqlite_temp_master table. Don't do this if the table being ALTERed is itself located in the temp database.
if ((where_ = WhereTempTriggers(parse, table)) != "")
{
parse.NestedParse(
"UPDATE sqlite_temp_master SET " +
"sql = sqlite_rename_trigger(sql, %Q), " +
"tbl_name = %Q " +
"WHERE %s;", nameAsString, nameAsString, where_);
C._tagfree(ctx, ref where_);
}
#endif
#if !(OMIT_FOREIGN_KEY) && !(OMIT_TRIGGER)
if ((ctx.Flags & Context.FLAG.ForeignKeys) != 0)
{
for (FKey p = Parse.FkReferences(table); p != null; p = p.NextTo)
{
Table from = p.From;
if (from != table)
{
ReloadTableSchema(parse, p.From, from.Name);
}
}
}
#endif
// Drop and reload the internal table schema.
ReloadTableSchema(parse, table, nameAsString);
exit_rename_table:
Expr.SrcListDelete(ctx, ref src);
C._tagfree(ctx, ref nameAsString);
ctx.Flags = savedDbFlags;
}
public static void DeleteFrom(Parse parse, SrcList tabList, Expr where_)
{
AuthContext sContext = new AuthContext(); // Authorization context
Context ctx = parse.Ctx; // Main database structure
if (parse.Errs != 0 || ctx.MallocFailed)
goto delete_from_cleanup;
Debug.Assert(tabList.Srcs == 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.
Table table = SrcList.Lookup(parse, tabList); // The table from which records will be deleted
if (table == null) goto delete_from_cleanup;
// Figure out if we have any triggers and if the table being deleted from is a view
#if !OMIT_TRIGGER
int dummy;
Trigger trigger = Triggers.Exist(parse, table, TK.DELETE, null, out dummy); // List of table triggers, if required
#if OMIT_VIEW
const bool isView = false;
#else
bool isView = (table.Select != null); // True if attempting to delete from a view
#endif
#else
const Trigger trigger = null;
bool isView = false;
#endif
// If pTab is really a view, make sure it has been initialized.
if (sqlite3ViewGetColumnNames(parse, table) != null || IsReadOnly(parse, table, (trigger != null)))
goto delete_from_cleanup;
int db = sqlite3SchemaToIndex(ctx, table.Schema); // Database number
Debug.Assert(db < ctx.DBs.length);
string dbName = ctx.DBs[db].Name; // Name of database holding pTab
ARC rcauth = Auth.Check(parse, AUTH.DELETE, table.Name, 0, dbName); // Value returned by authorization callback
Debug.Assert(rcauth == ARC.OK || rcauth == ARC.DENY || rcauth == ARC.IGNORE);
if (rcauth == ARC.DENY)
goto delete_from_cleanup;
Debug.Assert(!isView || trigger != null);
// Assign cursor number to the table and all its indices.
Debug.Assert(tabList.Srcs == 1);
int curId = tabList.Ids[0].Cursor = parse.Tabs++; // VDBE VdbeCursor number for pTab
Index idx; // For looping over indices of the table
for (idx = table.Index; idx != null; idx = idx.Next)
parse.Tabs++;
// Start the view context
if (isView)
Auth.ContextPush(parse, sContext, table.Name);
// Begin generating code.
Vdbe v = parse.GetVdbe(); // The virtual database engine
if (v == null)
goto delete_from_cleanup;
if (parse.Nested == 0) v.CountChanges();
parse.BeginWriteOperation(1, db);
// If we are trying to delete from a view, realize that view into a ephemeral table.
#if !OMIT_VIEW && !OMIT_TRIGGER
if (isView)
MaterializeView(parse, table, where_, curId);
#endif
// Resolve the column names in the WHERE clause.
NameContext sNC = new NameContext(); // Name context to resolve expressions in
sNC.Parse = parse;
sNC.SrcList = tabList;
if (sqlite3ResolveExprNames(sNC, ref where_) != 0)
goto delete_from_cleanup;
// Initialize the counter of the number of rows deleted, if we are counting rows.
int memCnt = -1; // Memory cell used for change counting
if ((ctx.Flags & Context.FLAG.CountRows) != 0)
{
memCnt = ++parse.Mems;
v.AddOp2(OP.Integer, 0, memCnt);
}
#if !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.
if (rcauth == ARC.OK && where_ == null && trigger == null && !IsVirtual(table) && !FKey.FkRequired(parse, table, null, 0))
{
Debug.Assert(!isView);
v.AddOp4(OP.Clear, table.Id, db, memCnt, table.Name, Vdbe.P4T.STATIC);
for (idx = table.Index; idx != null; idx = idx.Next)
{
Debug.Assert(idx.Schema == table.Schema);
v.AddOp2(OP.Clear, idx.Id, db);
}
}
else
#endif
// The usual case: There is a WHERE clause so we have to scan through the table and pick which records to delete.
{
int rowSet = ++parse.Mems; // Register for rowset of rows to delete
int rowid = ++parse.Mems; // Used for storing rowid values.
// Collect rowids of every row to be deleted.
v.AddOp2(OP.Null, 0, rowSet);
ExprList dummy = null;
WhereInfo winfo = Where.Begin(parse, tabList, where_, ref dummy, WHERE_DUPLICATES_OK, 0); // Information about the WHERE clause
if (winfo == null) goto delete_from_cleanup;
int regRowid = Expr.CodeGetColumn(parse, table, -1, curId, rowid); // Actual register containing rowids
v.AddOp2(OP.RowSetAdd, rowSet, regRowid);
if ((ctx.Flags & Context.FLAG.CountRows) != 0)
v.AddOp2(OP.AddImm, memCnt, 1);
Where.End(winfo);
// Delete every item whose key was written to the list during the database scan. We have to delete items after the scan is complete
// because deleting an item can change the scan order.
int end = v.MakeLabel();
// 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)
sqlite3OpenTableAndIndices(parse, table, curId, OP.OpenWrite);
int addr = v.AddOp3(OP.RowSetRead, rowSet, end, rowid);
// Delete the row
#if !OMIT_VIRTUALTABLE
if (IsVirtual(table))
{
VTable vtable = VTable.GetVTable(ctx, table);
VTable.MakeWritable(parse, table);
v.AddOp4(OP.VUpdate, 0, 1, rowid, vtable, Vdbe.P4T.VTAB);
v.ChangeP5(OE.Abort);
sqlite3MayAbort(parse);
}
else
#endif
{
int count = (parse.Nested == 0; // True to count changes
GenerateRowDelete(parse, table, curId, rowid, count, trigger, OE.Default);
}
// End of the delete loop
v.AddOp2(OP.Goto, 0, addr);
v.ResolveLabel(end);
// Close the cursors open on the table and its indexes.
if (!isView && !IsVirtual(table))
{
for (int i = 1, idx = table.Index; idx != null; i++, idx = idx.Next)
v.AddOp2(OP.Close, curId + i, idx.Id);
v.AddOp1(OP.Close, curId);
}
}
// Update the sqlite_sequence table by storing the content of the maximum rowid counter values recorded while inserting into
// autoincrement tables.
if (parse.Nested == 0 && parse.TriggerTab == null)
sqlite3AutoincrementEnd(parse);
// 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 ((ctx.Flags & Context.FLAG.CountRows) != 0 && parse.Nested == 0 && parse.TriggerTab == null)
{
v.AddOp2(OP.ResultRow, memCnt, 1);
v.SetNumCols(1);
v.SetColName(0, COLNAME_NAME, "rows deleted", SQLITE_STATIC);
}
delete_from_cleanup:
Auth.ContextPop(sContext);
SrcList.Delete(ctx, ref tabList);
Expr.Delete(ctx, ref where_);
return;
}
