join parameters support & many comments

VERSION

@@ -1 +1 @@
-xorm v0.5.2.0324
+xorm v0.5.2.0329

engine.go

@@ -54,6 +54,7 @@ type Engine struct {
 	disableGlobalCache bool
 }
 
+// ShowSQL show SQL statment or not on logger if log level is great than INFO
 func (engine *Engine) ShowSQL(show ...bool) {
 	engine.logger.ShowSQL(show...)
 	if len(show) == 0 {
@@ -63,6 +64,7 @@ func (engine *Engine) ShowSQL(show ...bool) {
 	}
 }
 
+// ShowExecTime show SQL statment and execute time or not on logger if log level is great than INFO
 func (engine *Engine) ShowExecTime(show ...bool) {
 	if len(show) == 0 {
 		engine.showExecTime = true
@@ -71,43 +73,51 @@ func (engine *Engine) ShowExecTime(show ...bool) {
 	}
 }
 
+// Logger return the logger interface
 func (engine *Engine) Logger() core.ILogger {
 	return engine.logger
 }
 
+// SetLogger set the new logger
 func (engine *Engine) SetLogger(logger core.ILogger) {
 	engine.logger = logger
 	engine.dialect.SetLogger(logger)
 }
 
+// SetDisableGlobalCache disable global cache or not
 func (engine *Engine) SetDisableGlobalCache(disable bool) {
 	if engine.disableGlobalCache != disable {
 		engine.disableGlobalCache = disable
 	}
 }
 
+// DriverName return the current sql driver's name
 func (engine *Engine) DriverName() string {
 	return engine.dialect.DriverName()
 }
 
+// DataSourceName return the current connection string
 func (engine *Engine) DataSourceName() string {
 	return engine.dialect.DataSourceName()
 }
 
+// SetMapper set the name mapping rules
 func (engine *Engine) SetMapper(mapper core.IMapper) {
 	engine.SetTableMapper(mapper)
 	engine.SetColumnMapper(mapper)
 }
 
+// SetTableMapper set the table name mapping rule
 func (engine *Engine) SetTableMapper(mapper core.IMapper) {
 	engine.TableMapper = mapper
 }
 
+// SetColumnMapper set the column name mapping rule
 func (engine *Engine) SetColumnMapper(mapper core.IMapper) {
 	engine.ColumnMapper = mapper
 }
 
-// If engine's database support batch insert records like
+// SupportInsertMany If engine's database support batch insert records like
 // "insert into user values (name, age), (name, age)".
 // When the return is ture, then engine.Insert(&users) will
 // generate batch sql and exeute.
@@ -115,13 +125,13 @@ func (engine *Engine) SupportInsertMany() bool {
 	return engine.dialect.SupportInsertMany()
 }
 
-// Engine's database use which charactor as quote.
+// QuoteStr Engine's database use which charactor as quote.
 // mysql, sqlite use ` and postgres use "
 func (engine *Engine) QuoteStr() string {
 	return engine.dialect.QuoteStr()
 }
 
-// Use QuoteStr quote the string sql
+// Quote Use QuoteStr quote the string sql
 func (engine *Engine) Quote(sql string) string {
 	return engine.quoteTable(sql)
 }
@@ -160,12 +170,12 @@ func (engine *Engine) quoteTable(keyName string) string {
 	return engine.dialect.QuoteStr() + keyName + engine.dialect.QuoteStr()
 }
 
-// A simple wrapper to dialect's core.SqlType method
+// SqlType A simple wrapper to dialect's core.SqlType method
 func (engine *Engine) SqlType(c *core.Column) string {
 	return engine.dialect.SqlType(c)
 }
 
-// Database's autoincrement statement
+// AutoIncrStr Database's autoincrement statement
 func (engine *Engine) AutoIncrStr() string {
 	return engine.dialect.AutoIncrStr()
 }
@@ -175,22 +185,17 @@ func (engine *Engine) SetMaxOpenConns(conns int) {
 	engine.db.SetMaxOpenConns(conns)
 }
 
-// @Deprecated
+// SetMaxIdleConns set the max idle connections on pool, default is 2
-func (engine *Engine) SetMaxConns(conns int) {
-	engine.SetMaxOpenConns(conns)
-}
-
-// SetMaxIdleConns
 func (engine *Engine) SetMaxIdleConns(conns int) {
 	engine.db.SetMaxIdleConns(conns)
 }
 
-// SetDefaltCacher set the default cacher. Xorm's default not enable cacher.
+// SetDefaultCacher set the default cacher. Xorm's default not enable cacher.
 func (engine *Engine) SetDefaultCacher(cacher core.Cacher) {
 	engine.Cacher = cacher
 }
 
-// If you has set default cacher, and you want temporilly stop use cache,
+// NoCache If you has set default cacher, and you want temporilly stop use cache,
 // you can use NoCache()
 func (engine *Engine) NoCache() *Session {
 	session := engine.NewSession()
@@ -198,13 +203,14 @@ func (engine *Engine) NoCache() *Session {
 	return session.NoCache()
 }
 
+// NoCascade If you do not want to auto cascade load object
 func (engine *Engine) NoCascade() *Session {
 	session := engine.NewSession()
 	session.IsAutoClose = true
 	return session.NoCascade()
 }
 
-// Set a table use a special cacher
+// MapCacher Set a table use a special cacher
 func (engine *Engine) MapCacher(bean interface{}, cacher core.Cacher) {
 	v := rValue(bean)
 	tb := engine.autoMapType(v)
@@ -216,15 +222,17 @@ func (engine *Engine) NewDB() (*core.DB, error) {
 	return core.OpenDialect(engine.dialect)
 }
 
+// DB return the wrapper of sql.DB
 func (engine *Engine) DB() *core.DB {
 	return engine.db
 }
 
+// Dialect return database dialect
 func (engine *Engine) Dialect() core.Dialect {
 	return engine.dialect
 }
 
-// New a session
+// NewSession New a session
 func (engine *Engine) NewSession() *Session {
 	session := &Session{Engine: engine}
 	session.Init()
@@ -287,37 +295,42 @@ func (engine *Engine) logSQLExecutionTime(sqlStr string, args []interface{}, exe
 	}
 }
 
+// LogError logging error
 func (engine *Engine) LogError(contents ...interface{}) {
 	engine.logger.Err(contents...)
 }
 
+// LogErrorf logging errorf
 func (engine *Engine) LogErrorf(format string, contents ...interface{}) {
 	engine.logger.Errf(format, contents...)
 }
 
-// logging info
+// LogInfo logging info
 func (engine *Engine) LogInfo(contents ...interface{}) {
 	engine.logger.Info(contents...)
 }
 
+// LogInfof logging infof
 func (engine *Engine) LogInfof(format string, contents ...interface{}) {
 	engine.logger.Infof(format, contents...)
 }
 
-// logging debug
+// LogDebug logging debug
 func (engine *Engine) LogDebug(contents ...interface{}) {
 	engine.logger.Debug(contents...)
 }
 
+// LogDebugf logging debugf
 func (engine *Engine) LogDebugf(format string, contents ...interface{}) {
 	engine.logger.Debugf(format, contents...)
 }
 
-// logging warn
+// LogWarn logging warn
 func (engine *Engine) LogWarn(contents ...interface{}) {
 	engine.logger.Warning(contents...)
 }
 
+// LogWarnf logging warnf
 func (engine *Engine) LogWarnf(format string, contents ...interface{}) {
 	engine.logger.Warningf(format, contents...)
 }
@@ -335,7 +348,7 @@ func (engine *Engine) Sql(querystring string, args ...interface{}) *Session {
 	return session.Sql(querystring, args...)
 }
 
-// Default if your struct has "created" or "updated" filed tag, the fields
+// NoAutoTime Default if your struct has "created" or "updated" filed tag, the fields
 // will automatically be filled with current time when Insert or Update
 // invoked. Call NoAutoTime if you dont' want to fill automatically.
 func (engine *Engine) NoAutoTime() *Session {
@@ -344,13 +357,14 @@ func (engine *Engine) NoAutoTime() *Session {
 	return session.NoAutoTime()
 }
 
+// NoAutoCondition disable auto generate Where condition from bean or not
 func (engine *Engine) NoAutoCondition(no ...bool) *Session {
 	session := engine.NewSession()
 	session.IsAutoClose = true
 	return session.NoAutoCondition(no...)
 }
 
-// Retrieve all tables, columns, indexes' informations from database.
+// DBMetas Retrieve all tables, columns, indexes' informations from database.
 func (engine *Engine) DBMetas() ([]*core.Table, error) {
 	tables, err := engine.dialect.GetTables()
 	if err != nil {
@@ -818,10 +832,10 @@ func (engine *Engine) OrderBy(order string) *Session {
 }
 
 // The join_operator should be one of INNER, LEFT OUTER, CROSS etc - this will be prepended to JOIN
-func (engine *Engine) Join(join_operator string, tablename interface{}, condition string) *Session {
+func (engine *Engine) Join(join_operator string, tablename interface{}, condition string, args ...interface{}) *Session {
 	session := engine.NewSession()
 	session.IsAutoClose = true
-	return session.Join(join_operator, tablename, condition)
+	return session.Join(join_operator, tablename, condition, args...)
 }
 
 // Generate Group By statement

logger.go

@@ -18,6 +18,7 @@ const (
 	DEFAULT_LOG_LEVEL  = core.LOG_DEBUG
 )
 
+// SimpleLogger is the default implment of core.ILogger
 type SimpleLogger struct {
 	DEBUG   *log.Logger
 	ERR     *log.Logger
@@ -29,14 +30,17 @@ type SimpleLogger struct {
 
 var _ core.ILogger = &SimpleLogger{}
 
+// NewSimpleLogger use a special io.Writer as logger output
 func NewSimpleLogger(out io.Writer) *SimpleLogger {
 	return NewSimpleLogger2(out, DEFAULT_LOG_PREFIX, DEFAULT_LOG_FLAG)
 }
 
+// NewSimpleLogger2 let you customrize your logger prefix and flag
 func NewSimpleLogger2(out io.Writer, prefix string, flag int) *SimpleLogger {
 	return NewSimpleLogger3(out, prefix, flag, DEFAULT_LOG_LEVEL)
 }
 
+// NewSimpleLogger3 let you customrize your logger prefix and flag and logLevel
 func NewSimpleLogger3(out io.Writer, prefix string, flag int, l core.LogLevel) *SimpleLogger {
 	return &SimpleLogger{
 		DEBUG: log.New(out, fmt.Sprintf("%s [debug] ", prefix), flag),
@@ -47,6 +51,7 @@ func NewSimpleLogger3(out io.Writer, prefix string, flag int, l core.LogLevel) *
 	}
 }
 
+// Err implement core.ILogger
 func (s *SimpleLogger) Err(v ...interface{}) (err error) {
 	if s.level <= core.LOG_ERR {
 		s.ERR.Println(v...)
@@ -54,6 +59,7 @@ func (s *SimpleLogger) Err(v ...interface{}) (err error) {
 	return
 }
 
+// Errf implement core.ILogger
 func (s *SimpleLogger) Errf(format string, v ...interface{}) (err error) {
 	if s.level <= core.LOG_ERR {
 		s.ERR.Printf(format, v...)
@@ -61,6 +67,7 @@ func (s *SimpleLogger) Errf(format string, v ...interface{}) (err error) {
 	return
 }
 
+// Debug implement core.ILogger
 func (s *SimpleLogger) Debug(v ...interface{}) (err error) {
 	if s.level <= core.LOG_DEBUG {
 		s.DEBUG.Println(v...)
@@ -68,6 +75,7 @@ func (s *SimpleLogger) Debug(v ...interface{}) (err error) {
 	return
 }
 
+// Debugf implement core.ILogger
 func (s *SimpleLogger) Debugf(format string, v ...interface{}) (err error) {
 	if s.level <= core.LOG_DEBUG {
 		s.DEBUG.Printf(format, v...)
@@ -75,6 +83,7 @@ func (s *SimpleLogger) Debugf(format string, v ...interface{}) (err error) {
 	return
 }
 
+// Info implement core.ILogger
 func (s *SimpleLogger) Info(v ...interface{}) (err error) {
 	if s.level <= core.LOG_INFO {
 		s.INFO.Println(v...)
@@ -82,6 +91,7 @@ func (s *SimpleLogger) Info(v ...interface{}) (err error) {
 	return
 }
 
+// Infof implement core.ILogger
 func (s *SimpleLogger) Infof(format string, v ...interface{}) (err error) {
 	if s.level <= core.LOG_INFO {
 		s.INFO.Printf(format, v...)
@@ -89,6 +99,7 @@ func (s *SimpleLogger) Infof(format string, v ...interface{}) (err error) {
 	return
 }
 
+// Warning implement core.ILogger
 func (s *SimpleLogger) Warning(v ...interface{}) (err error) {
 	if s.level <= core.LOG_WARNING {
 		s.WARN.Println(v...)
@@ -96,6 +107,7 @@ func (s *SimpleLogger) Warning(v ...interface{}) (err error) {
 	return
 }
 
+// Warningf implement core.ILogger
 func (s *SimpleLogger) Warningf(format string, v ...interface{}) (err error) {
 	if s.level <= core.LOG_WARNING {
 		s.WARN.Printf(format, v...)
@@ -103,15 +115,18 @@ func (s *SimpleLogger) Warningf(format string, v ...interface{}) (err error) {
 	return
 }
 
+// Level implement core.ILogger
 func (s *SimpleLogger) Level() core.LogLevel {
 	return s.level
 }
 
+// SetLevel implement core.ILogger
 func (s *SimpleLogger) SetLevel(l core.LogLevel) (err error) {
 	s.level = l
 	return
 }
 
+// ShowSQL implement core.ILogger
 func (s *SimpleLogger) ShowSQL(show ...bool) {
 	if len(show) == 0 {
 		s.showSQL = true
@@ -120,6 +135,7 @@ func (s *SimpleLogger) ShowSQL(show ...bool) {
 	s.showSQL = show[0]
 }
 
+// IsShowSQL implement core.ILogger
 func (s *SimpleLogger) IsShowSQL() bool {
 	return s.showSQL
 }

session.go

@@ -309,31 +309,32 @@ func (session *Session) Cascade(trueOrFalse ...bool) *Session {
 	return session
 }
 
-// Method NoCache ask this session do not retrieve data from cache system and
+// NoCache ask this session do not retrieve data from cache system and
 // get data from database directly.
 func (session *Session) NoCache() *Session {
 	session.Statement.UseCache = false
 	return session
 }
 
-//The join_operator should be one of INNER, LEFT OUTER, CROSS etc - this will be prepended to JOIN
+// Join join_operator should be one of INNER, LEFT OUTER, CROSS etc - this will be prepended to JOIN
-func (session *Session) Join(join_operator string, tablename interface{}, condition string) *Session {
+func (session *Session) Join(joinOperator string, tablename interface{}, condition string, args ...interface{}) *Session {
-	session.Statement.Join(join_operator, tablename, condition)
+	session.Statement.Join(joinOperator, tablename, condition, args...)
 	return session
 }
 
-// Generate Group By statement
+// GroupBy Generate Group By statement
 func (session *Session) GroupBy(keys string) *Session {
 	session.Statement.GroupBy(keys)
 	return session
 }
 
-// Generate Having statement
+// Having Generate Having statement
 func (session *Session) Having(conditions string) *Session {
 	session.Statement.Having(conditions)
 	return session
 }
 
+// DB db return the wrapper of sql.DB
 func (session *Session) DB() *core.DB {
 	if session.db == nil {
 		session.db = session.Engine.db
@@ -357,7 +358,7 @@ func (session *Session) Begin() error {
 	return nil
 }
 
-// When using transaction, you can rollback if any error
+// Rollback When using transaction, you can rollback if any error
 func (session *Session) Rollback() error {
 	if !session.IsAutoCommit && !session.IsCommitedOrRollbacked {
 		session.saveLastSQL(session.Engine.dialect.RollBackStr())
@@ -367,7 +368,7 @@ func (session *Session) Rollback() error {
 	return nil
 }
 
-// When using transaction, Commit will commit all operations.
+// Commit When using transaction, Commit will commit all operations.
 func (session *Session) Commit() error {
 	if !session.IsAutoCommit && !session.IsCommitedOrRollbacked {
 		session.saveLastSQL("COMMIT")
@@ -521,7 +522,7 @@ func (session *Session) Exec(sqlStr string, args ...interface{}) (sql.Result, er
 	return session.exec(sqlStr, args...)
 }
 
-// this function create a table according a bean
+// CreateTable create a table according a bean
 func (session *Session) CreateTable(bean interface{}) error {
 	v := rValue(bean)
 	session.Statement.RefTable = session.Engine.mapType(v)
@@ -534,7 +535,7 @@ func (session *Session) CreateTable(bean interface{}) error {
 	return session.createOneTable()
 }
 
-// create indexes
+// CreateIndexes create indexes
 func (session *Session) CreateIndexes(bean interface{}) error {
 	v := rValue(bean)
 	session.Statement.RefTable = session.Engine.mapType(v)
@@ -554,7 +555,7 @@ func (session *Session) CreateIndexes(bean interface{}) error {
 	return nil
 }
 
-// create uniques
+// CreateUniques create uniques
 func (session *Session) CreateUniques(bean interface{}) error {
 	v := rValue(bean)
 	session.Statement.RefTable = session.Engine.mapType(v)
@@ -1242,7 +1243,7 @@ func (session *Session) Find(rowsSlicePtr interface{}, condiBean ...interface{})
 	var sqlStr string
 	var args []interface{}
 	if session.Statement.RawSQL == "" {
-		var columnStr string = session.Statement.ColumnStr
+		var columnStr = session.Statement.ColumnStr
 		if len(session.Statement.selectStr) > 0 {
 			columnStr = session.Statement.selectStr
 		} else {
@@ -1265,11 +1266,11 @@ func (session *Session) Find(rowsSlicePtr interface{}, condiBean ...interface{})
 			}
 		}
 
-		session.Statement.Params = append(session.Statement.Params, session.Statement.BeanArgs...)
+		session.Statement.Params = append(session.Statement.joinArgs, append(session.Statement.Params, session.Statement.BeanArgs...)...)
 
 		session.Statement.attachInSql()
 
-		sqlStr = session.Statement.genSelectSql(columnStr)
+		sqlStr = session.Statement.genSelectSQL(columnStr)
 		args = session.Statement.Params
 		// for mssql and use limit
 		qs := strings.Count(sqlStr, "?")

statement.go

@@ -37,7 +37,7 @@ type exprParam struct {
 	expr    string
 }
 
-// statement save all the sql info for executing SQL
+// Statement save all the sql info for executing SQL
 type Statement struct {
 	RefTable        *core.Table
 	Engine          *Engine
@@ -48,6 +48,7 @@ type Statement struct {
 	Params          []interface{}
 	OrderStr        string
 	JoinStr         string
+	joinArgs        []interface{}
 	GroupByStr      string
 	HavingStr       string
 	ColumnStr       string
@@ -91,6 +92,7 @@ func (statement *Statement) Init() {
 	statement.OrderStr = ""
 	statement.UseCascade = true
 	statement.JoinStr = ""
+	statement.joinArgs = make([]interface{}, 0)
 	statement.GroupByStr = ""
 	statement.HavingStr = ""
 	statement.ColumnStr = ""
@@ -428,12 +430,27 @@ func buildUpdates(engine *Engine, table *core.Table, bean interface{},
 	return colNames, args
 }
 
+func (statement *Statement) needTableName() bool {
+	return len(statement.JoinStr) > 0
+}
+
+func (statement *Statement) colName(col *core.Column, tableName string) string {
+	if statement.needTableName() {
+		var nm = tableName
+		if len(statement.TableAlias) > 0 {
+			nm = statement.TableAlias
+		}
+		return statement.Engine.Quote(nm) + "." + statement.Engine.Quote(col.Name)
+	}
+	return statement.Engine.Quote(col.Name)
+}
+
 // Auto generating conditions according a struct
 func buildConditions(engine *Engine, table *core.Table, bean interface{},
 	includeVersion bool, includeUpdated bool, includeNil bool,
 	includeAutoIncr bool, allUseBool bool, useAllCols bool, unscoped bool,
 	mustColumnMap map[string]bool, tableName, aliasName string, addedTableName bool) ([]string, []interface{}) {
-	colNames := make([]string, 0)
+	var colNames []string
 	var args = make([]interface{}, 0)
 	for _, col := range table.Columns() {
 		if !includeVersion && col.IsVersion {
@@ -960,7 +977,7 @@ func (statement *Statement) Asc(colNames ...string) *Statement {
 }
 
 //The join_operator should be one of INNER, LEFT OUTER, CROSS etc - this will be prepended to JOIN
-func (statement *Statement) Join(join_operator string, tablename interface{}, condition string) *Statement {
+func (statement *Statement) Join(join_operator string, tablename interface{}, condition string, args ...interface{}) *Statement {
 	var buf bytes.Buffer
 	if len(statement.JoinStr) > 0 {
 		fmt.Fprintf(&buf, "%v %v JOIN ", statement.JoinStr, join_operator)
@@ -1003,6 +1020,7 @@ func (statement *Statement) Join(join_operator string, tablename interface{}, co
 
 	fmt.Fprintf(&buf, " ON %v", condition)
 	statement.JoinStr = buf.String()
+	statement.joinArgs = args
 	return statement
 }
 
@@ -1140,9 +1158,10 @@ func (statement *Statement) genGetSql(bean interface{}) (string, []interface{})
 	if len(statement.selectStr) > 0 {
 		columnStr = statement.selectStr
 	} else {
+		// TODO: always generate column names, not use * even if join
 		if len(statement.JoinStr) == 0 {
 			if len(columnStr) == 0 {
-				if statement.GroupByStr != "" {
+				if len(statement.GroupByStr) > 0 {
 					columnStr = statement.Engine.Quote(strings.Replace(statement.GroupByStr, ",", statement.Engine.Quote(","), -1))
 				} else {
 					columnStr = statement.genColumnStr()
@@ -1150,7 +1169,7 @@ func (statement *Statement) genGetSql(bean interface{}) (string, []interface{})
 			}
 		} else {
 			if len(columnStr) == 0 {
-				if statement.GroupByStr != "" {
+				if len(statement.GroupByStr) > 0 {
 					columnStr = statement.Engine.Quote(strings.Replace(statement.GroupByStr, ",", statement.Engine.Quote(","), -1))
 				} else {
 					columnStr = "*"
@@ -1160,7 +1179,7 @@ func (statement *Statement) genGetSql(bean interface{}) (string, []interface{})
 	}
 
 	statement.attachInSql() // !admpub!  fix bug:Iterate func missing "... IN (...)"
-	return statement.genSelectSql(columnStr), append(statement.Params, statement.BeanArgs...)
+	return statement.genSelectSQL(columnStr), append(append(statement.joinArgs, statement.Params...), statement.BeanArgs...)
 }
 
 func (s *Statement) genAddColumnStr(col *core.Column) (string, []interface{}) {
@@ -1203,15 +1222,15 @@ func (statement *Statement) genCountSql(bean interface{}) (string, []interface{}
 	}
 
 	// count(index fieldname) > count(0) > count(*)
-	var id string = "*"
+	var id = "*"
 	if statement.Engine.Dialect().DBType() == "ql" {
 		id = ""
 	}
 	statement.attachInSql()
-	return statement.genSelectSql(fmt.Sprintf("count(%v)", id)), append(statement.Params, statement.BeanArgs...)
+	return statement.genSelectSQL(fmt.Sprintf("count(%v)", id)), append(append(statement.joinArgs, statement.Params...), statement.BeanArgs...)
 }
 
-func (statement *Statement) genSelectSql(columnStr string) (a string) {
+func (statement *Statement) genSelectSQL(columnStr string) (a string) {
 	var distinct string
 	if statement.IsDistinct {
 		distinct = "DISTINCT "
@@ -1322,11 +1341,12 @@ func (statement *Statement) processIdParam() {
 	if statement.IdParam != nil {
 		if statement.Engine.dialect.DBType() != "ql" {
 			for i, col := range statement.RefTable.PKColumns() {
+				var colName = statement.colName(col, statement.TableName())
 				if i < len(*(statement.IdParam)) {
-					statement.And(fmt.Sprintf("%v %s ?", statement.Engine.Quote(col.Name),
+					statement.And(fmt.Sprintf("%v %s ?", colName,
 						statement.Engine.dialect.EqStr()), (*(statement.IdParam))[i])
 				} else {
-					statement.And(fmt.Sprintf("%v %s ?", statement.Engine.Quote(col.Name),
+					statement.And(fmt.Sprintf("%v %s ?", colName,
 						statement.Engine.dialect.EqStr()), "")
 				}
 			}

xorm.go

@@ -5,7 +5,6 @@
 package xorm
 
 import (
-	"errors"
 	"fmt"
 	"os"
 	"reflect"
@@ -17,7 +16,8 @@ import (
 )
 
 const (
-	Version string = "0.5.2.0324"
+	// Version show the xorm's version
+	Version string = "0.5.2.0329"
 )
 
 func regDrvsNDialects() bool {
@@ -49,13 +49,13 @@ func close(engine *Engine) {
 	engine.Close()
 }
 
-// new a db manager according to the parameter. Currently support four
+// NewEngine new a db manager according to the parameter. Currently support four
 // drivers
 func NewEngine(driverName string, dataSourceName string) (*Engine, error) {
 	regDrvsNDialects()
 	driver := core.QueryDriver(driverName)
 	if driver == nil {
-		return nil, errors.New(fmt.Sprintf("Unsupported driver name: %v", driverName))
+		return nil, fmt.Errorf("Unsupported driver name: %v", driverName)
 	}
 
 	uri, err := driver.Parse(driverName, dataSourceName)
@@ -65,7 +65,7 @@ func NewEngine(driverName string, dataSourceName string) (*Engine, error) {
 
 	dialect := core.QueryDialect(uri.DbType)
 	if dialect == nil {
-		return nil, errors.New(fmt.Sprintf("Unsupported dialect type: %v", uri.DbType))
+		return nil, fmt.Errorf("Unsupported dialect type: %v", uri.DbType)
 	}
 
 	db, err := core.Open(driverName, dataSourceName)
@@ -97,7 +97,7 @@ func NewEngine(driverName string, dataSourceName string) (*Engine, error) {
 	return engine, nil
 }
 
-// clone an engine
+// Clone clone an engine
 func (engine *Engine) Clone() (*Engine, error) {
 	return NewEngine(engine.DriverName(), engine.DataSourceName())
 }