static void ReloadTableSchema(Parse parse, Table table, string name) { Context ctx = parse.Ctx; string where_; #if !SQLITE_OMIT_TRIGGER Trigger trig; #endif Vdbe v = parse.GetVdbe(); if (C._NEVER(v == null)) { return; } Debug.Assert(Btree.HoldsAllMutexes(ctx)); int db = Prepare.SchemaToIndex(ctx, table.Schema); // Index of database containing pTab Debug.Assert(db >= 0); #if !OMIT_TRIGGER // Drop any table triggers from the internal schema. for (trig = Trigger.List(parse, table); trig != null; trig = trig.Next) { int trigDb = Prepare.SchemaToIndex(ctx, trig.Schema); Debug.Assert(trigDb == db || trigDb == 1); v.AddOp4(OP.DropTrigger, trigDb, 0, 0, trig.Name, 0); } #endif // Drop the table and index from the internal schema. v.AddOp4(OP.DropTable, db, 0, 0, table.Name, 0); // Reload the table, index and permanent trigger schemas. where_ = C._mtagprintf(ctx, "tbl_name=%Q", name); if (where_ == null) { return; } v.AddParseSchemaOp(db, where_); #if !OMIT_TRIGGER // Now, if the table is not stored in the temp database, reload any temp triggers. Don't use IN(...) in case SQLITE_OMIT_SUBQUERY is defined. if ((where_ = WhereTempTriggers(parse, table)) != "") { v.AddParseSchemaOp(1, where_); } #endif }
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 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 sqlite3Update(Parse parse, SrcList tabList, ExprList changes, Expr where_, OE onError) { int i, j; // Loop counters AuthContext sContext = new AuthContext(); // The authorization context Context ctx = parse.Ctx; // The database structure if (parse.Errs != 0 || ctx.MallocFailed) { goto update_cleanup; } Debug.Assert(tabList.Srcs == 1); // Locate the table which we want to update. Table table = sqlite3SrcListLookup(parse, tabList); // The table to be updated if (table == null) { goto update_cleanup; } int db = sqlite3SchemaToIndex(ctx, table.Schema); // Database containing the table being updated // Figure out if we have any triggers and if the table being updated is a view. #if !OMIT_TRIGGER int tmask = 0; // Mask of TRIGGER_BEFORE|TRIGGER_AFTER Trigger trigger = sqlite3TriggersExist(parse, table, TK.UPDATE, changes, out tmask); // List of triggers on pTab, if required #if OMIT_VIEW const bool isView = false; #else bool isView = (table.Select != null); // True when updating a view (INSTEAD OF trigger) #endif Debug.Assert(trigger != null || tmask == 0); #else const Trigger trigger = null; const int tmask = 0; const bool isView = false; #endif if (sqlite3ViewGetColumnNames(parse, table) != 0 || sqlite3IsReadOnly(parse, table, tmask)) { goto update_cleanup; } int[] xrefs = new int[table.Cols.length]; // xrefs[i] is the index in pChanges->a[] of the an expression for the i-th column of the table. xrefs[i]==-1 if the i-th column is not changed. if (xrefs == null) { goto update_cleanup; } for (i = 0; i < table.Cols.length; i++) { xrefs[i] = -1; } // Allocate a cursors for the main database table and for all indices. The index cursors might not be used, but if they are used they // need to occur right after the database cursor. So go ahead and allocate enough space, just in case. int curId; // VDBE Cursor number of pTab tabList.Ids[0].Cursor = curId = parse.Tabs++; Index idx; // For looping over indices for (idx = table.Index; idx != null; idx = idx.Next) { parse.Tabs++; } // Initialize the name-context NameContext sNC = new NameContext(); // The name-context to resolve expressions in sNC.Parse = parse; sNC.SrcList = tabList; // Resolve the column names in all the expressions of the of the UPDATE statement. Also find the column index // for each column to be updated in the pChanges array. For each column to be updated, make sure we have authorization to change that column. bool chngRowid = false; // True if the record number is being changed Expr rowidExpr = null; // Expression defining the new record number for (i = 0; i < changes.Exprs; i++) { if (sqlite3ResolveExprNames(sNC, ref changes.Ids[i].Expr) != 0) { goto update_cleanup; } for (j = 0; j < table.Cols.length; j++) { if (string.Equals(table.Cols[j].Name, changes.Ids[i].Name, StringComparison.OrdinalIgnoreCase)) { if (j == table.PKey) { chngRowid = true; rowidExpr = changes.Ids[i].Expr; } xrefs[j] = i; break; } } if (j >= table.Cols.length) { if (Expr::IsRowid(changes.Ids[i].Name)) { chngRowid = true; rowidExpr = changes.Ids[i].Expr; } else { parse.ErrorMsg("no such column: %s", changes.Ids[i].Name); parse.CheckSchema = 1; goto update_cleanup; } } #if !OMIT_AUTHORIZATION { ARC rc = Auth.Check(parse, AUTH.UPDATE, table.Name, table.Cols[j].Name, ctx.DBs[db].Name); if (rc == ARC.DENY) { goto update_cleanup; } else if (rc == ARC.IGNORE) { xrefs[j] = -1; } } #endif } bool hasFK = sqlite3FkRequired(parse, table, xrefs, chngRowid ? 1 : 0); // True if foreign key processing is required // Allocate memory for the array aRegIdx[]. There is one entry in the array for each index associated with table being updated. Fill in // the value with a register number for indices that are to be used and with zero for unused indices. int idxLength; // Number of indices that need updating for (idxLength = 0, idx = table.Index; idx != null; idx = idx.Next, idxLength++) { ; } int[] regIdxs = null; // One register assigned to each index to be updated if (idxLength > 0) { regIdxs = new int[idxLength]; if (regIdxs == null) { goto update_cleanup; } } for (j = 0, idx = table.Index; idx != null; idx = idx.Next, j++) { int regId; if (hasFK || chngRowid) { regId = ++parse.Mems; } else { regId = 0; for (i = 0; i < idx.Columns.length; i++) { if (xrefs[idx.Columns[i]] >= 0) { regId = ++parse.Mems; break; } } } regIdxs[j] = regId; } // Begin generating code. Vdbe v = parse.GetVdbe(); // The virtual database engine if (v == null) { goto update_cleanup; } if (parse.Nested == 0) { v.CountChanges(); } parse.BeginWriteOperation(1, db); #if !OMIT_VIRTUALTABLE // Virtual tables must be handled separately if (IsVirtual(table)) { UpdateVirtualTable(parse, tabList, table, changes, rowidExpr, xrefs, where_, onError); where_ = null; tabList = null; goto update_cleanup; } #endif // Register Allocations int regRowCount = 0; // A count of rows changed int regOldRowid; // The old rowid int regNewRowid; // The new rowid int regNew; int regOld = 0; int regRowSet = 0; // Rowset of rows to be updated // Allocate required registers. regOldRowid = regNewRowid = ++parse.Mems; if (trigger != null || hasFK) { regOld = parse.Mems + 1; parse.Mems += table.Cols.length; } if (chngRowid || trigger != null || hasFK) { regNewRowid = ++parse.Mems; } regNew = parse.Mems + 1; parse.Mems += table.Cols.length; // Start the view context. if (isView) { Auth.ContextPush(parse, sContext, table.Name); } // If we are trying to update a view, realize that view into a ephemeral table. #if !OMIT_VIEW && !OMIT_TRIGGER if (isView) { sqlite3MaterializeView(parse, table, where_, curId); } #endif // Resolve the column names in all the expressions in the WHERE clause. if (sqlite3ResolveExprNames(sNC, ref where_) != 0) { goto update_cleanup; } // Begin the database scan v.AddOp2(OP.Null, 0, regOldRowid); ExprList dummy = null; WhereInfo winfo = Where.Begin(parse, tabList, where_, ref dummy, WHERE.ONEPASS_DESIRED); // Information about the WHERE clause if (winfo == null) { goto update_cleanup; } bool okOnePass = winfo.OkOnePass; // True for one-pass algorithm without the FIFO // Remember the rowid of every item to be updated. v.AddOp2(OP.Rowid, curId, regOldRowid); if (!okOnePass) { v.AddOp2(OP.RowSetAdd, regRowSet, regOldRowid); } // End the database scan loop. Where.End(winfo); // Initialize the count of updated rows if ((ctx.Flags & Context.FLAG.CountRows) != 0 && parse.TriggerTab == null) { regRowCount = ++parse.Mems; v.AddOp2(OP.Integer, 0, regRowCount); } bool openAll = false; // True if all indices need to be opened if (!isView) { // Open every index that needs updating. Note that if any index could potentially invoke a REPLACE conflict resolution // action, then we need to open all indices because we might need to be deleting some records. if (!okOnePass) { sqlite3OpenTable(parse, curId, db, table, OP.OpenWrite); } if (onError == OE.Replace) { openAll = true; } else { openAll = false; for (idx = table.Index; idx != null; idx = idx.Next) { if (idx.OnError == OE.Replace) { openAll = true; break; } } } for (i = 0, idx = table.Index; idx != null; idx = idx.Next, i++) { if (openAll || regIdxs[i] > 0) { KeyInfo key = sqlite3IndexKeyinfo(parse, idx); v.AddOp4(OP.OpenWrite, curId + i + 1, idx.Id, db, key, Vdbe.P4T.KEYINFO_HANDOFF); Debug.Assert(parse.Tabs > curId + i + 1); } } } // Top of the update loop int addr = 0; // VDBE instruction address of the start of the loop if (okOnePass) { int a1 = v.AddOp1(OP.NotNull, regOldRowid); addr = v.AddOp0(OP.Goto); v.JumpHere(a1); } else { addr = v.AddOp3(OP.RowSetRead, regRowSet, 0, regOldRowid); } // Make cursor iCur point to the record that is being updated. If this record does not exist for some reason (deleted by a trigger, // for example, then jump to the next iteration of the RowSet loop. v.AddOp3(OP.NotExists, curId, addr, regOldRowid); // If the record number will change, set register regNewRowid to contain the new value. If the record number is not being modified, // then regNewRowid is the same register as regOldRowid, which is already populated. Debug.Assert(chngRowid || trigger != null || hasFK || regOldRowid == regNewRowid); if (chngRowid) { Expr.Code(parse, rowidExpr, regNewRowid); v.AddOp1(OP.MustBeInt, regNewRowid); } // If there are triggers on this table, populate an array of registers with the required old.* column data. if (hasFK || trigger != null) { uint oldmask = (hasFK ? sqlite3FkOldmask(parse, table) : 0); oldmask |= sqlite3TriggerColmask(parse, trigger, changes, 0, TRIGGER_BEFORE | TRIGGER_AFTER, table, onError); for (i = 0; i < table.Cols.length; i++) { if (xrefs[i] < 0 || oldmask == 0xffffffff || (i < 32 && 0 != (oldmask & (1 << i)))) { Expr.CodeGetColumnOfTable(v, table, curId, i, regOld + i); } else { v.AddOp2(OP.Null, 0, regOld + i); } } if (!chngRowid) { v.AddOp2(OP.Copy, regOldRowid, regNewRowid); } } // Populate the array of registers beginning at regNew with the new row data. This array is used to check constaints, create the new // table and index records, and as the values for any new.* references made by triggers. // // If there are one or more BEFORE triggers, then do not populate the registers associated with columns that are (a) not modified by // this UPDATE statement and (b) not accessed by new.* references. The values for registers not modified by the UPDATE must be reloaded from // the database after the BEFORE triggers are fired anyway (as the trigger may have modified them). So not loading those that are not going to // be used eliminates some redundant opcodes. int newmask = (int)sqlite3TriggerColmask(parse, trigger, changes, 1, TRIGGER_BEFORE, table, onError); // Mask of NEW.* columns accessed by BEFORE triggers for (i = 0; i < table.Cols.length; i++) { if (i == table.PKey) { //v.AddOp2(OP.Null, 0, regNew + i); } else { j = xrefs[i]; if (j >= 0) { Expr.Code(parse, changes.Ids[j].Expr, regNew + i); } else if ((tmask & TRIGGER_BEFORE) == 0 || i > 31 || (newmask & (1 << i)) != 0) { // This branch loads the value of a column that will not be changed into a register. This is done if there are no BEFORE triggers, or // if there are one or more BEFORE triggers that use this value via a new.* reference in a trigger program. C.ASSERTCOVERAGE(i == 31); C.ASSERTCOVERAGE(i == 32); v.AddOp3(OP.Column, curId, i, regNew + i); v.ColumnDefault(table, i, regNew + i); } } } // Fire any BEFORE UPDATE triggers. This happens before constraints are verified. One could argue that this is wrong. if ((tmask & TRIGGER_BEFORE) != 0) { v.AddOp2(OP.Affinity, regNew, table.Cols.length); sqlite3TableAffinityStr(v, table); sqlite3CodeRowTrigger(parse, trigger, TK.UPDATE, changes, TRIGGER_BEFORE, table, regOldRowid, onError, addr); // The row-trigger may have deleted the row being updated. In this case, jump to the next row. No updates or AFTER triggers are // required. This behavior - what happens when the row being updated is deleted or renamed by a BEFORE trigger - is left undefined in the documentation. v.AddOp3(OP.NotExists, curId, addr, regOldRowid); // If it did not delete it, the row-trigger may still have modified some of the columns of the row being updated. Load the values for // all columns not modified by the update statement into their registers in case this has happened. for (i = 0; i < table.Cols.length; i++) { if (xrefs[i] < 0 && i != table.PKey) { v.AddOp3(OP.Column, curId, i, regNew + i); v.ColumnDefault(table, i, regNew + i); } } } if (!isView) { // Do constraint checks. int dummy2; sqlite3GenerateConstraintChecks(parse, table, curId, regNewRowid, regIdxs, (chngRowid ? regOldRowid : 0), true, onError, addr, out dummy2); // Do FK constraint checks. if (hasFK) { sqlite3FkCheck(parse, table, regOldRowid, 0); } // Delete the index entries associated with the current record. int j1 = v.AddOp3(OP.NotExists, curId, 0, regOldRowid); // Address of jump instruction sqlite3GenerateRowIndexDelete(parse, table, curId, regIdxs); // If changing the record number, delete the old record. if (hasFK || chngRowid) { v.AddOp2(OP.Delete, curId, 0); } v.JumpHere(j1); if (hasFK) { sqlite3FkCheck(parse, table, 0, regNewRowid); } // Insert the new index entries and the new record. sqlite3CompleteInsertion(parse, table, curId, regNewRowid, regIdxs, true, false, false); // 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 updated. if (hasFK) { sqlite3FkActions(parse, table, changes, regOldRowid); } } // Increment the row counter if ((ctx.Flags & Context.FLAG.CountRows) != 0 && parse.TriggerTab == null) { v.AddOp2(OP.AddImm, regRowCount, 1); } sqlite3CodeRowTrigger(parse, trigger, TK.UPDATE, changes, TRIGGER_AFTER, table, regOldRowid, onError, addr); // Repeat the above with the next record to be updated, until all record selected by the WHERE clause have been updated. v.AddOp2(OP.Goto, 0, addr); v.JumpHere(addr); // Close all tables Debug.Assert(regIdxs != null); for (i = 0, idx = table.Index; idx != null; idx = idx.Next, i++) { if (openAll || regIdxs[i] > 0) { v.AddOp2(OP.Close, curId + i + 1, 0); } } v.AddOp2(OP.Close, curId, 0); // 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 changed. 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.TriggerTab == null && parse.Nested == 0) { v.AddOp2(OP.ResultRow, regRowCount, 1); v.SetNumCols(1); v.SetColName(0, COLNAME_NAME, "rows updated", SQLITE_STATIC); } update_cleanup: #if !OMIT_AUTHORIZATION Auth.ContextPop(sContext); #endif C._tagfree(ctx, ref regIdxs); C._tagfree(ctx, ref xrefs); SrcList.Delete(ctx, ref tabList); ExprList.Delete(ctx, ref changes); Expr.Delete(ctx, ref where_); return; }
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; }
static void AnalyzeOneTable(Parse parse, Table table, Index onlyIdx, int statCurId, int memId) { Context ctx = parse.Ctx; // Database handle int i; // Loop counter int regTabname = memId++; // Register containing table name int regIdxname = memId++; // Register containing index name int regSampleno = memId++; // Register containing next sample number int regCol = memId++; // Content of a column analyzed table int regRec = memId++; // Register holding completed record int regTemp = memId++; // Temporary use register int regRowid = memId++; // Rowid for the inserted record Vdbe v = parse.GetVdbe(); // The virtual machine being built up if (v == null || C._NEVER(table == null)) { return; } // Do not gather statistics on views or virtual tables or system tables if (table.Id == 0 || table.Name.StartsWith("sqlite_", StringComparison.OrdinalIgnoreCase)) { return; } Debug.Assert(Btree.HoldsAllMutexes(ctx)); int db = sqlite3SchemaToIndex(ctx, table.Schema); // Index of database containing pTab Debug.Assert(db >= 0); Debug.Assert(Btree.SchemaMutexHeld(ctx, db, null)); #if !OMIT_AUTHORIZATION if (Auth.Check(parse, AUTH.ANALYZE, table.Name, 0, ctx.DBs[db].Name)) { return; } #endif // Establish a read-lock on the table at the shared-cache level. sqlite3TableLock(parse, db, table.Id, 0, table.Name); int zeroRows = -1; // Jump from here if number of rows is zero int idxCurId = parse.Tabs++; // Cursor open on index being analyzed v.AddOp4(OP.String8, 0, regTabname, 0, table.Name, 0); for (Index idx = table.Index; idx != null; idx = idx.Next) // An index to being analyzed { if (onlyIdx != null && onlyIdx != idx) { continue; } v.NoopComment("Begin analysis of %s", idx.Name); int cols = idx.Columns.length; int[] chngAddrs = C._tagalloc <int>(ctx, cols); // Array of jump instruction addresses if (chngAddrs == null) { continue; } KeyInfo key = sqlite3IndexKeyinfo(parse, idx); if (memId + 1 + (cols * 2) > parse.Mems) { parse.Mems = memId + 1 + (cols * 2); } // Open a cursor to the index to be analyzed. Debug.Assert(db == sqlite3SchemaToIndex(ctx, idx.Schema)); v.AddOp4(OP.OpenRead, idxCurId, idx.Id, db, key, Vdbe.P4T.KEYINFO_HANDOFF); v.VdbeComment("%s", idx.Name); // Populate the registers containing the index names. v.AddOp4(OP.String8, 0, regIdxname, 0, idx.Name, 0); #if ENABLE_STAT3 bool once = false; // One-time initialization if (once) { once = false; sqlite3OpenTable(parse, tabCurId, db, table, OP.OpenRead); } v.AddOp2(OP.Count, idxCurId, regCount); v.AddOp2(OP.Integer, STAT3_SAMPLES, regTemp1); v.AddOp2(OP.Integer, 0, regNumEq); v.AddOp2(OP.Integer, 0, regNumLt); v.AddOp2(OP.Integer, -1, regNumDLt); v.AddOp3(OP.Null, 0, regSample, regAccum); v.AddOp4(OP.Function, 1, regCount, regAccum, (object)_stat3InitFuncdef, Vdbe.P4T.FUNCDEF); v.ChangeP5(2); #endif // The block of memory cells initialized here is used as follows. // // iMem: // The total number of rows in the table. // // iMem+1 .. iMem+nCol: // Number of distinct entries in index considering the left-most N columns only, where N is between 1 and nCol, // inclusive. // // iMem+nCol+1 .. Mem+2*nCol: // Previous value of indexed columns, from left to right. // // Cells iMem through iMem+nCol are initialized to 0. The others are initialized to contain an SQL NULL. for (i = 0; i <= cols; i++) { v.AddOp2(OP.Integer, 0, memId + i); } for (i = 0; i < cols; i++) { v.AddOp2(OP.Null, 0, memId + cols + i + 1); } // Start the analysis loop. This loop runs through all the entries in the index b-tree. int endOfLoop = v.MakeLabel(); // The end of the loop v.AddOp2(OP.Rewind, idxCurId, endOfLoop); int topOfLoop = v.CurrentAddr(); // The top of the loop v.AddOp2(OP.AddImm, memId, 1); int addrIfNot = 0; // address of OP_IfNot for (i = 0; i < cols; i++) { v.AddOp3(OP.Column, idxCurId, i, regCol); if (i == 0) // Always record the very first row { addrIfNot = v.AddOp1(OP.IfNot, memId + 1); } Debug.Assert(idx.CollNames != null && idx.CollNames[i] != null); CollSeq coll = sqlite3LocateCollSeq(parse, idx.CollNames[i]); chngAddrs[i] = v.AddOp4(OP.Ne, regCol, 0, memId + cols + i + 1, coll, Vdbe.P4T.COLLSEQ); v.ChangeP5(SQLITE_NULLEQ); v.VdbeComment("jump if column %d changed", i); #if ENABLE_STAT3 if (i == 0) { v.AddOp2(OP.AddImm, regNumEq, 1); v.VdbeComment("incr repeat count"); } #endif } v.AddOp2(OP.Goto, 0, endOfLoop); for (i = 0; i < cols; i++) { v.JumpHere(chngAddrs[i]); // Set jump dest for the OP_Ne if (i == 0) { v.JumpHere(addrIfNot); // Jump dest for OP_IfNot #if ENABLE_STAT3 v.AddOp4(OP.Function, 1, regNumEq, regTemp2, (object)Stat3PushFuncdef, Vdbe.P4T.FUNCDEF); v.ChangeP5(5); v.AddOp3(OP.Column, idxCurId, idx.Columns.length, regRowid); v.AddOp3(OP.Add, regNumEq, regNumLt, regNumLt); v.AddOp2(OP.AddImm, regNumDLt, 1); v.AddOp2(OP.Integer, 1, regNumEq); #endif } v.AddOp2(OP.AddImm, memId + i + 1, 1); v.AddOp3(OP.Column, idxCurId, i, memId + cols + i + 1); } C._tagfree(ctx, chngAddrs); // Always jump here after updating the iMem+1...iMem+1+nCol counters v.ResolveLabel(endOfLoop); v.AddOp2(OP.Next, idxCurId, topOfLoop); v.AddOp1(OP.Close, idxCurId); #if ENABLE_STAT3 v.AddOp4(OP.Function, 1, regNumEq, regTemp2, (object)Stat3PushFuncdef, Vdbe.P4T.FUNCDEF); v.ChangeP5(5); v.AddOp2(OP.Integer, -1, regLoop); int shortJump = v.AddOp2(OP_AddImm, regLoop, 1); // Instruction address v.AddOp4(OP.Function, 1, regAccum, regTemp1, (object)Stat3GetFuncdef, Vdbe.P4T.FUNCDEF); v.ChangeP5(2); v.AddOp1(OP.IsNull, regTemp1); v.AddOp3(OP.NotExists, tabCurId, shortJump, regTemp1); v.AddOp3(OP.Column, tabCurId, idx->Columns[0], regSample); sqlite3ColumnDefault(v, table, idx->Columns[0], regSample); v.AddOp4(OP.Function, 1, regAccum, regNumEq, (object)Stat3GetFuncdef, Vdbe.P4T.FUNCDEF); v.ChangeP5(3); v.AddOp4(OP.Function, 1, regAccum, regNumLt, (object)Stat3GetFuncdef, Vdbe.P4T.FUNCDEF); v.ChangeP5(4); v.AddOp4(OP.Function, 1, regAccum, regNumDLt, (object)Stat3GetFuncdef, Vdbe.P4T.FUNCDEF); v.ChangeP5(5); v.AddOp4(OP.MakeRecord, regTabname, 6, regRec, "bbbbbb", 0); v.AddOp2(OP.NewRowid, statCurId + 1, regNewRowid); v.AddOp3(OP.Insert, statCurId + 1, regRec, regNewRowid); v.AddOp2(OP.Goto, 0, shortJump); v.JumpHere(shortJump + 2); #endif // Store the results in sqlite_stat1. // // The result is a single row of the sqlite_stat1 table. The first two columns are the names of the table and index. The third column // is a string composed of a list of integer statistics about the index. The first integer in the list is the total number of entries // in the index. There is one additional integer in the list for each column of the table. This additional integer is a guess of how many // rows of the table the index will select. If D is the count of distinct values and K is the total number of rows, then the integer is computed // as: // I = (K+D-1)/D // If K==0 then no entry is made into the sqlite_stat1 table. // If K>0 then it is always the case the D>0 so division by zero is never possible. v.AddOp2(OP_SCopy, memId, regStat1); if (zeroRows < 0) { zeroRows = v.AddOp1(OP.IfNot, memId); } for (i = 0; i < cols; i++) { v.AddOp4(OP.String8, 0, regTemp, 0, " ", 0); v.AddOp3(OP.Concat, regTemp, regStat1, regStat1); v.AddOp3(OP.Add, memId, memId + i + 1, regTemp); v.AddOp2(OP.AddImm, regTemp, -1); v.AddOp3(OP.Divide, memId + i + 1, regTemp, regTemp); v.AddOp1(OP.ToInt, regTemp); v.AddOp3(OP.Concat, regTemp, regStat1, regStat1); } v.AddOp4(OP.MakeRecord, regTabname, 3, regRec, "aaa", 0); v.AddOp2(OP.NewRowid, statCurId, regNewRowid); v.AddOp3(OP.Insert, statCurId, regRec, regNewRowid); v.ChangeP5(OPFLAG_APPEND); } // If the table has no indices, create a single sqlite_stat1 entry containing NULL as the index name and the row count as the content. if (table.Index == null) { v.AddOp3(OP.OpenRead, idxCurId, table->Id, db); v.VdbeComment("%s", table->Name); v.AddOp2(OP.Count, idxCurId, regStat1); v.AddOp1(OP.Close, idxCurId); zeroRows = v.AddOp1(OP.IfNot, regStat1); } else { v.JumpHere(zeroRows); zeroRows = v.AddOp0(OP_Goto); } v.AddOp2(OP.Null, 0, regIdxname); v.AddOp4(OP.MakeRecord, regTabname, 3, regRec, "aaa", 0); v.AddOp2(OP.NewRowid, statCurId, regNewRowid); v.AddOp3(OP.Insert, statCurId, regRec, regNewRowid); v.ChangeP5(OPFLAG_APPEND); if (parse.Mems < regRec) { parse.Mems = regRec; } v.JumpHere(zeroRows); }