update mssql drive to last working version 20180314172330-6a30f4e59a44 (#7306)

vendor/github.com/denisenkom/go-mssqldb/mssql.go

@@ -1,122 +1,269 @@
 package mssql
 
 import (
+	"context"
 	"database/sql"
 	"database/sql/driver"
 	"encoding/binary"
 	"errors"
 	"fmt"
 	"io"
-	"log"
 	"math"
 	"net"
+	"reflect"
 	"strings"
 	"time"
 )
 
+var driverInstance = &Driver{processQueryText: true}
+var driverInstanceNoProcess = &Driver{processQueryText: false}
+
 func init() {
-	sql.Register("mssql", &MssqlDriver{})
+	sql.Register("mssql", driverInstance)
+	sql.Register("sqlserver", driverInstanceNoProcess)
+	createDialer = func(p *connectParams) dialer {
+		return tcpDialer{&net.Dialer{Timeout: p.dial_timeout, KeepAlive: p.keepAlive}}
+	}
 }
 
-type MssqlDriver struct {
-	log *log.Logger
+// Abstract the dialer for testing and for non-TCP based connections.
+type dialer interface {
+	Dial(ctx context.Context, addr string) (net.Conn, error)
 }
 
-func (d *MssqlDriver) SetLogger(logger *log.Logger) {
-	d.log = logger
+var createDialer func(p *connectParams) dialer
+
+type tcpDialer struct {
+	nd *net.Dialer
 }
 
-func CheckBadConn(err error) error {
-	if err == io.EOF {
+func (d tcpDialer) Dial(ctx context.Context, addr string) (net.Conn, error) {
+	return d.nd.DialContext(ctx, "tcp", addr)
+}
+
+type Driver struct {
+	log optionalLogger
+
+	processQueryText bool
+}
+
+// OpenConnector opens a new connector. Useful to dial with a context.
+func (d *Driver) OpenConnector(dsn string) (*Connector, error) {
+	params, err := parseConnectParams(dsn)
+	if err != nil {
+		return nil, err
+	}
+	return &Connector{
+		params: params,
+		driver: d,
+	}, nil
+}
+
+func (d *Driver) Open(dsn string) (driver.Conn, error) {
+	return d.open(context.Background(), dsn)
+}
+
+// Connector holds the parsed DSN and is ready to make a new connection
+// at any time.
+//
+// In the future, settings that cannot be passed through a string DSN
+// may be set directly on the connector.
+type Connector struct {
+	params connectParams
+	driver *Driver
+}
+
+// Connect to the server and return a TDS connection.
+func (c *Connector) Connect(ctx context.Context) (driver.Conn, error) {
+	return c.driver.connect(ctx, c.params)
+}
+
+// Driver underlying the Connector.
+func (c *Connector) Driver() driver.Driver {
+	return c.driver
+}
+
+func SetLogger(logger Logger) {
+	driverInstance.SetLogger(logger)
+	driverInstanceNoProcess.SetLogger(logger)
+}
+
+func (d *Driver) SetLogger(logger Logger) {
+	d.log = optionalLogger{logger}
+}
+
+type Conn struct {
+	sess           *tdsSession
+	transactionCtx context.Context
+
+	processQueryText bool
+	connectionGood   bool
+
+	outs map[string]interface{}
+}
+
+func (c *Conn) checkBadConn(err error) error {
+	// this is a hack to address Issue #275
+	// we set connectionGood flag to false if
+	// error indicates that connection is not usable
+	// but we return actual error instead of ErrBadConn
+	// this will cause connection to stay in a pool
+	// but next request to this connection will return ErrBadConn
+
+	// it might be possible to revise this hack after
+	// https://github.com/golang/go/issues/20807
+	// is implemented
+	switch err {
+	case nil:
+		return nil
+	case io.EOF:
 		return driver.ErrBadConn
+	case driver.ErrBadConn:
+		// It is an internal programming error if driver.ErrBadConn
+		// is ever passed to this function. driver.ErrBadConn should
+		// only ever be returned in response to a *mssql.Conn.connectionGood == false
+		// check in the external facing API.
+		panic("driver.ErrBadConn in checkBadConn. This should not happen.")
 	}
 
-	switch e := err.(type) {
+	switch err.(type) {
 	case net.Error:
-		if e.Timeout() {
-			return e
-		}
-		return driver.ErrBadConn
+		c.connectionGood = false
+		return err
+	case StreamError:
+		c.connectionGood = false
+		return err
 	default:
 		return err
 	}
 }
 
-type MssqlConn struct {
-	sess *tdsSession
+func (c *Conn) clearOuts() {
+	c.outs = nil
 }
 
-func (c *MssqlConn) Commit() error {
+func (c *Conn) simpleProcessResp(ctx context.Context) error {
+	tokchan := make(chan tokenStruct, 5)
+	go processResponse(ctx, c.sess, tokchan, c.outs)
+	c.clearOuts()
+	for tok := range tokchan {
+		switch token := tok.(type) {
+		case doneStruct:
+			if token.isError() {
+				return c.checkBadConn(token.getError())
+			}
+		case error:
+			return c.checkBadConn(token)
+		}
+	}
+	return nil
+}
+
+func (c *Conn) Commit() error {
+	if !c.connectionGood {
+		return driver.ErrBadConn
+	}
+	if err := c.sendCommitRequest(); err != nil {
+		return c.checkBadConn(err)
+	}
+	return c.simpleProcessResp(c.transactionCtx)
+}
+
+func (c *Conn) sendCommitRequest() error {
 	headers := []headerStruct{
 		{hdrtype: dataStmHdrTransDescr,
 			data: transDescrHdr{c.sess.tranid, 1}.pack()},
 	}
 	if err := sendCommitXact(c.sess.buf, headers, "", 0, 0, ""); err != nil {
-		return err
-	}
-
-	tokchan := make(chan tokenStruct, 5)
-	go processResponse(c.sess, tokchan)
-	for tok := range tokchan {
-		switch token := tok.(type) {
-		case error:
-			return token
+		if c.sess.logFlags&logErrors != 0 {
+			c.sess.log.Printf("Failed to send CommitXact with %v", err)
 		}
+		c.connectionGood = false
+		return fmt.Errorf("Faild to send CommitXact: %v", err)
 	}
 	return nil
 }
 
-func (c *MssqlConn) Rollback() error {
+func (c *Conn) Rollback() error {
+	if !c.connectionGood {
+		return driver.ErrBadConn
+	}
+	if err := c.sendRollbackRequest(); err != nil {
+		return c.checkBadConn(err)
+	}
+	return c.simpleProcessResp(c.transactionCtx)
+}
+
+func (c *Conn) sendRollbackRequest() error {
 	headers := []headerStruct{
 		{hdrtype: dataStmHdrTransDescr,
 			data: transDescrHdr{c.sess.tranid, 1}.pack()},
 	}
 	if err := sendRollbackXact(c.sess.buf, headers, "", 0, 0, ""); err != nil {
-		return err
-	}
-
-	tokchan := make(chan tokenStruct, 5)
-	go processResponse(c.sess, tokchan)
-	for tok := range tokchan {
-		switch token := tok.(type) {
-		case error:
-			return token
+		if c.sess.logFlags&logErrors != 0 {
+			c.sess.log.Printf("Failed to send RollbackXact with %v", err)
 		}
+		c.connectionGood = false
+		return fmt.Errorf("Failed to send RollbackXact: %v", err)
 	}
 	return nil
 }
 
-func (c *MssqlConn) Begin() (driver.Tx, error) {
+func (c *Conn) Begin() (driver.Tx, error) {
+	return c.begin(context.Background(), isolationUseCurrent)
+}
+
+func (c *Conn) begin(ctx context.Context, tdsIsolation isoLevel) (tx driver.Tx, err error) {
+	if !c.connectionGood {
+		return nil, driver.ErrBadConn
+	}
+	err = c.sendBeginRequest(ctx, tdsIsolation)
+	if err != nil {
+		return nil, c.checkBadConn(err)
+	}
+	tx, err = c.processBeginResponse(ctx)
+	if err != nil {
+		return nil, c.checkBadConn(err)
+	}
+	return
+}
+
+func (c *Conn) sendBeginRequest(ctx context.Context, tdsIsolation isoLevel) error {
+	c.transactionCtx = ctx
 	headers := []headerStruct{
 		{hdrtype: dataStmHdrTransDescr,
 			data: transDescrHdr{0, 1}.pack()},
 	}
-	if err := sendBeginXact(c.sess.buf, headers, 0, ""); err != nil {
-		return nil, CheckBadConn(err)
-	}
-	tokchan := make(chan tokenStruct, 5)
-	go processResponse(c.sess, tokchan)
-	for tok := range tokchan {
-		switch token := tok.(type) {
-		case error:
-			if c.sess.tranid != 0 {
-				return nil, token
-			}
-			return nil, CheckBadConn(token)
+	if err := sendBeginXact(c.sess.buf, headers, tdsIsolation, ""); err != nil {
+		if c.sess.logFlags&logErrors != 0 {
+			c.sess.log.Printf("Failed to send BeginXact with %v", err)
 		}
+		c.connectionGood = false
+		return fmt.Errorf("Failed to send BiginXant: %v", err)
+	}
+	return nil
+}
+
+func (c *Conn) processBeginResponse(ctx context.Context) (driver.Tx, error) {
+	if err := c.simpleProcessResp(ctx); err != nil {
+		return nil, err
 	}
 	// successful BEGINXACT request will return sess.tranid
 	// for started transaction
 	return c, nil
 }
 
-func (d *MssqlDriver) Open(dsn string) (driver.Conn, error) {
+func (d *Driver) open(ctx context.Context, dsn string) (*Conn, error) {
 	params, err := parseConnectParams(dsn)
 	if err != nil {
 		return nil, err
 	}
+	return d.connect(ctx, params)
+}
 
-	sess, err := connect(params)
+// connect to the server, using the provided context for dialing only.
+func (d *Driver) connect(ctx context.Context, params connectParams) (*Conn, error) {
+	sess, err := connect(ctx, d.log, params)
 	if err != nil {
 		// main server failed, try fail-over partner
 		if params.failOverPartner == "" {
@@ -128,24 +275,29 @@ func (d *MssqlDriver) Open(dsn string) (driver.Conn, error) {
 			params.port = params.failOverPort
 		}
 
-		sess, err = connect(params)
+		sess, err = connect(ctx, d.log, params)
 		if err != nil {
 			// fail-over partner also failed, now fail
 			return nil, err
 		}
 	}
 
-	conn := &MssqlConn{sess}
-	conn.sess.log = (*Logger)(d.log)
+	conn := &Conn{
+		sess:             sess,
+		transactionCtx:   context.Background(),
+		processQueryText: d.processQueryText,
+		connectionGood:   true,
+	}
+	conn.sess.log = d.log
 	return conn, nil
 }
 
-func (c *MssqlConn) Close() error {
+func (c *Conn) Close() error {
 	return c.sess.buf.transport.Close()
 }
 
-type MssqlStmt struct {
-	c          *MssqlConn
+type Stmt struct {
+	c          *Conn
 	query      string
 	paramCount int
 	notifSub   *queryNotifSub
@@ -157,16 +309,30 @@ type queryNotifSub struct {
 	timeout uint32
 }
 
-func (c *MssqlConn) Prepare(query string) (driver.Stmt, error) {
-	q, paramCount := parseParams(query)
-	return &MssqlStmt{c, q, paramCount, nil}, nil
+func (c *Conn) Prepare(query string) (driver.Stmt, error) {
+	if !c.connectionGood {
+		return nil, driver.ErrBadConn
+	}
+	if len(query) > 10 && strings.EqualFold(query[:10], "INSERTBULK") {
+		return c.prepareCopyIn(query)
+	}
+
+	return c.prepareContext(context.Background(), query)
 }
 
-func (s *MssqlStmt) Close() error {
+func (c *Conn) prepareContext(ctx context.Context, query string) (*Stmt, error) {
+	paramCount := -1
+	if c.processQueryText {
+		query, paramCount = parseParams(query)
+	}
+	return &Stmt{c, query, paramCount, nil}, nil
+}
+
+func (s *Stmt) Close() error {
 	return nil
 }
 
-func (s *MssqlStmt) SetQueryNotification(id, options string, timeout time.Duration) {
+func (s *Stmt) SetQueryNotification(id, options string, timeout time.Duration) {
 	to := uint32(timeout / time.Second)
 	if to < 1 {
 		to = 1
@@ -174,183 +340,273 @@ func (s *MssqlStmt) SetQueryNotification(id, options string, timeout time.Durati
 	s.notifSub = &queryNotifSub{id, options, to}
 }
 
-func (s *MssqlStmt) NumInput() int {
+func (s *Stmt) NumInput() int {
 	return s.paramCount
 }
 
-func (s *MssqlStmt) sendQuery(args []driver.Value) (err error) {
+func (s *Stmt) sendQuery(args []namedValue) (err error) {
 	headers := []headerStruct{
 		{hdrtype: dataStmHdrTransDescr,
 			data: transDescrHdr{s.c.sess.tranid, 1}.pack()},
 	}
 
 	if s.notifSub != nil {
-		headers = append(headers, headerStruct{hdrtype: dataStmHdrQueryNotif,
-			data: queryNotifHdr{s.notifSub.msgText, s.notifSub.options, s.notifSub.timeout}.pack()})
+		headers = append(headers,
+			headerStruct{
+				hdrtype: dataStmHdrQueryNotif,
+				data: queryNotifHdr{
+					s.notifSub.msgText,
+					s.notifSub.options,
+					s.notifSub.timeout,
+				}.pack(),
+			})
 	}
 
-	if len(args) != s.paramCount {
-		return errors.New(fmt.Sprintf("sql: expected %d parameters, got %d", s.paramCount, len(args)))
-	}
+	// no need to check number of parameters here, it is checked by database/sql
 	if s.c.sess.logFlags&logSQL != 0 {
 		s.c.sess.log.Println(s.query)
 	}
 	if s.c.sess.logFlags&logParams != 0 && len(args) > 0 {
 		for i := 0; i < len(args); i++ {
-			s.c.sess.log.Printf("\t@p%d\t%v\n", i+1, args[i])
+			if len(args[i].Name) > 0 {
+				s.c.sess.log.Printf("\t@%s\t%v\n", args[i].Name, args[i].Value)
+			} else {
+				s.c.sess.log.Printf("\t@p%d\t%v\n", i+1, args[i].Value)
+			}
 		}
 
 	}
 	if len(args) == 0 {
 		if err = sendSqlBatch72(s.c.sess.buf, s.query, headers); err != nil {
-			if s.c.sess.tranid != 0 {
-				return err
+			if s.c.sess.logFlags&logErrors != 0 {
+				s.c.sess.log.Printf("Failed to send SqlBatch with %v", err)
 			}
-			return CheckBadConn(err)
+			s.c.connectionGood = false
+			return fmt.Errorf("failed to send SQL Batch: %v", err)
 		}
 	} else {
-		params := make([]Param, len(args)+2)
-		decls := make([]string, len(args))
-		params[0], err = s.makeParam(s.query)
-		if err != nil {
-			return
-		}
-		for i, val := range args {
-			params[i+2], err = s.makeParam(val)
+		proc := Sp_ExecuteSql
+		var params []Param
+		if isProc(s.query) {
+			proc.name = s.query
+			params, _, err = s.makeRPCParams(args, 0)
+		} else {
+			var decls []string
+			params, decls, err = s.makeRPCParams(args, 2)
 			if err != nil {
 				return
 			}
-			name := fmt.Sprintf("@p%d", i+1)
-			params[i+2].Name = name
-			decls[i] = fmt.Sprintf("%s %s", name, makeDecl(params[i+2].ti))
+			params[0] = makeStrParam(s.query)
+			params[1] = makeStrParam(strings.Join(decls, ","))
 		}
-		params[1], err = s.makeParam(strings.Join(decls, ","))
-		if err != nil {
-			return
-		}
-		if err = sendRpc(s.c.sess.buf, headers, Sp_ExecuteSql, 0, params); err != nil {
-			if s.c.sess.tranid != 0 {
-				return err
+		if err = sendRpc(s.c.sess.buf, headers, proc, 0, params); err != nil {
+			if s.c.sess.logFlags&logErrors != 0 {
+				s.c.sess.log.Printf("Failed to send Rpc with %v", err)
 			}
-			return CheckBadConn(err)
+			s.c.connectionGood = false
+			return fmt.Errorf("Failed to send RPC: %v", err)
 		}
 	}
 	return
 }
 
-func (s *MssqlStmt) Query(args []driver.Value) (res driver.Rows, err error) {
-	if err = s.sendQuery(args); err != nil {
-		return
+// isProc takes the query text in s and determines if it is a stored proc name
+// or SQL text.
+func isProc(s string) bool {
+	if len(s) == 0 {
+		return false
 	}
+	if s[0] == '[' && s[len(s)-1] == ']' && strings.ContainsAny(s, "\n\r") == false {
+		return true
+	}
+	return !strings.ContainsAny(s, " \t\n\r;")
+}
+
+func (s *Stmt) makeRPCParams(args []namedValue, offset int) ([]Param, []string, error) {
+	var err error
+	params := make([]Param, len(args)+offset)
+	decls := make([]string, len(args))
+	for i, val := range args {
+		params[i+offset], err = s.makeParam(val.Value)
+		if err != nil {
+			return nil, nil, err
+		}
+		var name string
+		if len(val.Name) > 0 {
+			name = "@" + val.Name
+		} else {
+			name = fmt.Sprintf("@p%d", val.Ordinal)
+		}
+		params[i+offset].Name = name
+		decls[i] = fmt.Sprintf("%s %s", name, makeDecl(params[i+offset].ti))
+	}
+	return params, decls, nil
+}
+
+type namedValue struct {
+	Name    string
+	Ordinal int
+	Value   driver.Value
+}
+
+func convertOldArgs(args []driver.Value) []namedValue {
+	list := make([]namedValue, len(args))
+	for i, v := range args {
+		list[i] = namedValue{
+			Ordinal: i + 1,
+			Value:   v,
+		}
+	}
+	return list
+}
+
+func (s *Stmt) Query(args []driver.Value) (driver.Rows, error) {
+	return s.queryContext(context.Background(), convertOldArgs(args))
+}
+
+func (s *Stmt) queryContext(ctx context.Context, args []namedValue) (rows driver.Rows, err error) {
+	if !s.c.connectionGood {
+		return nil, driver.ErrBadConn
+	}
+	if err = s.sendQuery(args); err != nil {
+		return nil, s.c.checkBadConn(err)
+	}
+	return s.processQueryResponse(ctx)
+}
+
+func (s *Stmt) processQueryResponse(ctx context.Context) (res driver.Rows, err error) {
 	tokchan := make(chan tokenStruct, 5)
-	go processResponse(s.c.sess, tokchan)
+	ctx, cancel := context.WithCancel(ctx)
+	go processResponse(ctx, s.c.sess, tokchan, s.c.outs)
+	s.c.clearOuts()
 	// process metadata
-	var cols []string
+	var cols []columnStruct
 loop:
 	for tok := range tokchan {
 		switch token := tok.(type) {
-		// by ignoring DONE token we effectively
-		// skip empty result-sets
-		// this improves results in queryes like that:
+		// By ignoring DONE token we effectively
+		// skip empty result-sets.
+		// This improves results in queries like that:
 		// set nocount on; select 1
 		// see TestIgnoreEmptyResults test
 		//case doneStruct:
 		//break loop
 		case []columnStruct:
-			cols = make([]string, len(token))
-			for i, col := range token {
-				cols[i] = col.ColName
-			}
+			cols = token
 			break loop
-		case error:
-			if s.c.sess.tranid != 0 {
-				return nil, token
+		case doneStruct:
+			if token.isError() {
+				return nil, s.c.checkBadConn(token.getError())
 			}
-			return nil, CheckBadConn(token)
+		case error:
+			return nil, s.c.checkBadConn(token)
 		}
 	}
-	return &MssqlRows{sess: s.c.sess, tokchan: tokchan, cols: cols}, nil
+	res = &Rows{stmt: s, tokchan: tokchan, cols: cols, cancel: cancel}
+	return
 }
 
-func (s *MssqlStmt) Exec(args []driver.Value) (res driver.Result, err error) {
-	if err = s.sendQuery(args); err != nil {
-		return
+func (s *Stmt) Exec(args []driver.Value) (driver.Result, error) {
+	return s.exec(context.Background(), convertOldArgs(args))
+}
+
+func (s *Stmt) exec(ctx context.Context, args []namedValue) (res driver.Result, err error) {
+	if !s.c.connectionGood {
+		return nil, driver.ErrBadConn
 	}
+	if err = s.sendQuery(args); err != nil {
+		return nil, s.c.checkBadConn(err)
+	}
+	if res, err = s.processExec(ctx); err != nil {
+		return nil, s.c.checkBadConn(err)
+	}
+	return
+}
+
+func (s *Stmt) processExec(ctx context.Context) (res driver.Result, err error) {
 	tokchan := make(chan tokenStruct, 5)
-	go processResponse(s.c.sess, tokchan)
+	go processResponse(ctx, s.c.sess, tokchan, s.c.outs)
+	s.c.clearOuts()
 	var rowCount int64
 	for token := range tokchan {
 		switch token := token.(type) {
 		case doneInProcStruct:
 			if token.Status&doneCount != 0 {
-				rowCount = int64(token.RowCount)
+				rowCount += int64(token.RowCount)
 			}
 		case doneStruct:
 			if token.Status&doneCount != 0 {
-				rowCount = int64(token.RowCount)
+				rowCount += int64(token.RowCount)
+			}
+			if token.isError() {
+				return nil, token.getError()
 			}
 		case error:
-			if s.c.sess.logFlags&logErrors != 0 {
-				s.c.sess.log.Println("got error:", token)
-			}
-			if s.c.sess.tranid != 0 {
-				return nil, token
-			}
-			return nil, CheckBadConn(token)
+			return nil, token
 		}
 	}
-	return &MssqlResult{s.c, rowCount}, nil
+	return &Result{s.c, rowCount}, nil
 }
 
-type MssqlRows struct {
-	sess    *tdsSession
-	cols    []string
+type Rows struct {
+	stmt    *Stmt
+	cols    []columnStruct
 	tokchan chan tokenStruct
 
-	nextCols []string
+	nextCols []columnStruct
+
+	cancel func()
 }
 
-func (rc *MssqlRows) Close() error {
+func (rc *Rows) Close() error {
+	rc.cancel()
 	for _ = range rc.tokchan {
 	}
 	rc.tokchan = nil
 	return nil
 }
 
-func (rc *MssqlRows) Columns() (res []string) {
-	return rc.cols
+func (rc *Rows) Columns() (res []string) {
+	res = make([]string, len(rc.cols))
+	for i, col := range rc.cols {
+		res[i] = col.ColName
+	}
+	return
 }
 
-func (rc *MssqlRows) Next(dest []driver.Value) (err error) {
+func (rc *Rows) Next(dest []driver.Value) error {
+	if !rc.stmt.c.connectionGood {
+		return driver.ErrBadConn
+	}
 	if rc.nextCols != nil {
 		return io.EOF
 	}
 	for tok := range rc.tokchan {
 		switch tokdata := tok.(type) {
 		case []columnStruct:
-			cols := make([]string, len(tokdata))
-			for i, col := range tokdata {
-				cols[i] = col.ColName
-			}
-			rc.nextCols = cols
+			rc.nextCols = tokdata
 			return io.EOF
 		case []interface{}:
 			for i := range dest {
 				dest[i] = tokdata[i]
 			}
 			return nil
+		case doneStruct:
+			if tokdata.isError() {
+				return rc.stmt.c.checkBadConn(tokdata.getError())
+			}
 		case error:
-			return tokdata
+			return rc.stmt.c.checkBadConn(tokdata)
 		}
 	}
 	return io.EOF
 }
 
-func (rc *MssqlRows) HasNextResultSet() bool {
+func (rc *Rows) HasNextResultSet() bool {
 	return rc.nextCols != nil
 }
 
-func (rc *MssqlRows) NextResultSet() error {
+func (rc *Rows) NextResultSet() error {
 	rc.cols = rc.nextCols
 	rc.nextCols = nil
 	if rc.cols == nil {
@@ -359,11 +615,69 @@ func (rc *MssqlRows) NextResultSet() error {
 	return nil
 }
 
-func (s *MssqlStmt) makeParam(val driver.Value) (res Param, err error) {
+// It should return
+// the value type that can be used to scan types into. For example, the database
+// column type "bigint" this should return "reflect.TypeOf(int64(0))".
+func (r *Rows) ColumnTypeScanType(index int) reflect.Type {
+	return makeGoLangScanType(r.cols[index].ti)
+}
+
+// RowsColumnTypeDatabaseTypeName may be implemented by Rows. It should return the
+// database system type name without the length. Type names should be uppercase.
+// Examples of returned types: "VARCHAR", "NVARCHAR", "VARCHAR2", "CHAR", "TEXT",
+// "DECIMAL", "SMALLINT", "INT", "BIGINT", "BOOL", "[]BIGINT", "JSONB", "XML",
+// "TIMESTAMP".
+func (r *Rows) ColumnTypeDatabaseTypeName(index int) string {
+	return makeGoLangTypeName(r.cols[index].ti)
+}
+
+// RowsColumnTypeLength may be implemented by Rows. It should return the length
+// of the column type if the column is a variable length type. If the column is
+// not a variable length type ok should return false.
+// If length is not limited other than system limits, it should return math.MaxInt64.
+// The following are examples of returned values for various types:
+//   TEXT          (math.MaxInt64, true)
+//   varchar(10)   (10, true)
+//   nvarchar(10)  (10, true)
+//   decimal       (0, false)
+//   int           (0, false)
+//   bytea(30)     (30, true)
+func (r *Rows) ColumnTypeLength(index int) (int64, bool) {
+	return makeGoLangTypeLength(r.cols[index].ti)
+}
+
+// It should return
+// the precision and scale for decimal types. If not applicable, ok should be false.
+// The following are examples of returned values for various types:
+//   decimal(38, 4)    (38, 4, true)
+//   int               (0, 0, false)
+//   decimal           (math.MaxInt64, math.MaxInt64, true)
+func (r *Rows) ColumnTypePrecisionScale(index int) (int64, int64, bool) {
+	return makeGoLangTypePrecisionScale(r.cols[index].ti)
+}
+
+// The nullable value should
+// be true if it is known the column may be null, or false if the column is known
+// to be not nullable.
+// If the column nullability is unknown, ok should be false.
+func (r *Rows) ColumnTypeNullable(index int) (nullable, ok bool) {
+	nullable = r.cols[index].Flags&colFlagNullable != 0
+	ok = true
+	return
+}
+
+func makeStrParam(val string) (res Param) {
+	res.ti.TypeId = typeNVarChar
+	res.buffer = str2ucs2(val)
+	res.ti.Size = len(res.buffer)
+	return
+}
+
+func (s *Stmt) makeParam(val driver.Value) (res Param, err error) {
 	if val == nil {
-		res.ti.TypeId = typeNVarChar
+		res.ti.TypeId = typeNull
 		res.buffer = nil
-		res.ti.Size = 2
+		res.ti.Size = 0
 		return
 	}
 	switch val := val.(type) {
@@ -382,9 +696,7 @@ func (s *MssqlStmt) makeParam(val driver.Value) (res Param, err error) {
 		res.ti.Size = len(val)
 		res.buffer = val
 	case string:
-		res.ti.TypeId = typeNVarChar
-		res.buffer = str2ucs2(val)
-		res.ti.Size = len(res.buffer)
+		res = makeStrParam(val)
 	case bool:
 		res.ti.TypeId = typeBitN
 		res.ti.Size = 1
@@ -425,22 +737,21 @@ func (s *MssqlStmt) makeParam(val driver.Value) (res Param, err error) {
 			binary.LittleEndian.PutUint32(res.buffer[4:8], uint32(tm))
 		}
 	default:
-		err = fmt.Errorf("mssql: unknown type for %T", val)
-		return
+		return s.makeParamExtra(val)
 	}
 	return
 }
 
-type MssqlResult struct {
-	c            *MssqlConn
+type Result struct {
+	c            *Conn
 	rowsAffected int64
 }
 
-func (r *MssqlResult) RowsAffected() (int64, error) {
+func (r *Result) RowsAffected() (int64, error) {
 	return r.rowsAffected, nil
 }
 
-func (r *MssqlResult) LastInsertId() (int64, error) {
+func (r *Result) LastInsertId() (int64, error) {
 	s, err := r.c.Prepare("select cast(@@identity as bigint)")
 	if err != nil {
 		return 0, err