diff --git a/DONATOR.MD b/DONATOR.MD
index 5cd691921..c7a954564 100644
--- a/DONATOR.MD
+++ b/DONATOR.MD
@@ -69,7 +69,7 @@ We currently accept donation by Alipay/WechatPay, please note your github/gitee
 |1*1x|wechat|￥100.00| 
 |[ywanbing](https://github.com/ywanbing)|wechat|￥66.66| 
 |[侯哥](http://www.macnie.com)|wechat|￥10.00| 
-|如果🍋|alipay|￥100.00| 错误的奶茶^_^
+|如果🍋|alipay|￥100.00| 错过的奶茶^_^
 |蔡蔡|wechat|￥666.00| gf真强大，让项目省心
 
 
diff --git a/database/gdb/gdb.go b/database/gdb/gdb.go
index ad37c2c5d..209857895 100644
--- a/database/gdb/gdb.go
+++ b/database/gdb/gdb.go
@@ -89,6 +89,8 @@ type DB interface {
 	SetSchema(schema string)
 	GetSchema() string
 	GetPrefix() string
+	SetDryRun(dryrun bool)
+	GetDryRun() bool
 	SetLogger(logger *glog.Logger)
 	GetLogger() *glog.Logger
 	SetMaxIdleConnCount(n int)
@@ -124,6 +126,7 @@ type Core struct {
 	debug            *gtype.Bool   // Enable debug mode for the database.
 	cache            *gcache.Cache // Cache manager.
 	schema           *gtype.String // Custom schema for this object.
+	dryrun           *gtype.Bool   // Dry run.
 	prefix           string        // Table prefix.
 	logger           *glog.Logger  // Logger.
 	maxIdleConnCount int           // Max idle connection count.
@@ -234,6 +237,7 @@ func New(name ...string) (db DB, err error) {
 				debug:            gtype.NewBool(),
 				cache:            gcache.New(),
 				schema:           gtype.NewString(),
+				dryrun:           gtype.NewBool(),
 				logger:           glog.New(),
 				prefix:           node.Prefix,
 				maxIdleConnCount: gDEFAULT_CONN_MAX_IDLE_COUNT,
@@ -401,5 +405,8 @@ func (c *Core) getSqlDb(master bool, schema ...string) (sqlDb *sql.DB, err error
 	if node.Debug {
 		c.DB.SetDebug(node.Debug)
 	}
+	if node.Debug {
+		c.DB.SetDryRun(node.DryRun)
+	}
 	return
 }
diff --git a/database/gdb/gdb_core.go b/database/gdb/gdb_core.go
index 43aaa4b6b..31e064230 100644
--- a/database/gdb/gdb_core.go
+++ b/database/gdb/gdb_core.go
@@ -99,7 +99,11 @@ func (c *Core) DoExec(link Link, sql string, args ...interface{}) (result sql.Re
 	sql, args = c.DB.HandleSqlBeforeCommit(link, sql, args)
 	if c.DB.GetDebug() {
 		mTime1 := gtime.TimestampMilli()
-		result, err = link.Exec(sql, args...)
+		if !c.DB.GetDryRun() {
+			result, err = link.Exec(sql, args...)
+		} else {
+			result = new(SqlResult)
+		}
 		mTime2 := gtime.TimestampMilli()
 		s := &Sql{
 			Sql:    sql,
@@ -111,7 +115,11 @@ func (c *Core) DoExec(link Link, sql string, args ...interface{}) (result sql.Re
 		}
 		c.writeSqlToLogger(s)
 	} else {
-		result, err = link.Exec(sql, args...)
+		if !c.DB.GetDryRun() {
+			result, err = link.Exec(sql, args...)
+		} else {
+			result = new(SqlResult)
+		}
 	}
 	return result, formatError(err, sql, args...)
 }
diff --git a/database/gdb/gdb_core_config.go b/database/gdb/gdb_core_config.go
index 46e52ef54..3c78665a6 100644
--- a/database/gdb/gdb_core_config.go
+++ b/database/gdb/gdb_core_config.go
@@ -36,6 +36,7 @@ type ConfigNode struct {
 	Role             string        // (Optional, "master" in default) Node role, used for master-slave mode: master, slave.
 	Debug            bool          // (Optional) Debug mode enables debug information logging and output.
 	Prefix           string        // (Optional) Table prefix.
+	DryRun           bool          // (Optional) Dry run, which does SELECT but no INSERT/UPDATE/DELETE statements.
 	Weight           int           // (Optional) Weight for load balance calculating, it's useless if there's just one node.
 	Charset          string        // (Optional, "utf8mb4" in default) Custom charset when operating on database.
 	LinkInfo         string        // (Optional) Custom link information, when it is used, configuration Host/Port/User/Pass/Name are ignored.
@@ -142,24 +143,19 @@ func (c *Core) SetMaxConnLifetime(d time.Duration) {
 
 // String returns the node as string.
 func (node *ConfigNode) String() string {
-	if node.LinkInfo != "" {
-		return node.LinkInfo
-	}
 	return fmt.Sprintf(
-		`%s@%s:%s,%s,%s,%s,%s,%v,%d-%d-%d`,
+		`%s@%s:%s,%s,%s,%s,%s,%v,%d-%d-%d#%s`,
 		node.User, node.Host, node.Port,
 		node.Name, node.Type, node.Role, node.Charset, node.Debug,
 		node.MaxIdleConnCount,
 		node.MaxOpenConnCount,
 		node.MaxConnLifetime,
+		node.LinkInfo,
 	)
 }
 
 // SetDebug enables/disables the debug mode.
 func (c *Core) SetDebug(debug bool) {
-	if c.debug.Val() == debug {
-		return
-	}
 	c.debug.Set(debug)
 }
 
@@ -178,6 +174,16 @@ func (c *Core) GetPrefix() string {
 	return c.prefix
 }
 
+// SetDryRun enables/disables the DryRun feature.
+func (c *Core) SetDryRun(dryrun bool) {
+	c.dryrun.Set(dryrun)
+}
+
+// GetDryRun returns the DryRun value.
+func (c *Core) GetDryRun() bool {
+	return c.dryrun.Val()
+}
+
 // SetSchema changes the schema for this database connection object.
 // Importantly note that when schema configuration changed for the database,
 // it affects all operations on the database object in the future.
diff --git a/database/gdb/gdb_driver_mysql.go b/database/gdb/gdb_driver_mysql.go
index 2e781fd86..02f81660b 100644
--- a/database/gdb/gdb_driver_mysql.go
+++ b/database/gdb/gdb_driver_mysql.go
@@ -10,6 +10,7 @@ import (
 	"database/sql"
 	"fmt"
 	"github.com/gogf/gf/internal/intlog"
+	"github.com/gogf/gf/text/gregex"
 	"github.com/gogf/gf/text/gstr"
 
 	_ "github.com/go-sql-driver/mysql"
@@ -33,6 +34,10 @@ func (d *DriverMysql) Open(config *ConfigNode) (*sql.DB, error) {
 	var source string
 	if config.LinkInfo != "" {
 		source = config.LinkInfo
+		// Custom changing the schema in runtime.
+		if config.Name != "" {
+			source, _ = gregex.ReplaceString(`/([\w\.\-]+)+`, "/"+config.Name, source)
+		}
 	} else {
 		source = fmt.Sprintf(
 			"%s:%s@tcp(%s:%s)/%s?charset=%s&multiStatements=true&parseTime=true&loc=Local",
diff --git a/database/gdb/gdb_result.go b/database/gdb/gdb_result.go
index 2ebfc55fe..4a1dd7d77 100644
--- a/database/gdb/gdb_result.go
+++ b/database/gdb/gdb_result.go
@@ -38,10 +38,16 @@ func (r *SqlResult) RowsAffected() (int64, error) {
 	if r.affected > 0 {
 		return r.affected, nil
 	}
+	if r.result == nil {
+		return 0, nil
+	}
 	return r.result.RowsAffected()
 }
 
 // see sql.Result.LastInsertId
 func (r *SqlResult) LastInsertId() (int64, error) {
+	if r.result == nil {
+		return 0, nil
+	}
 	return r.result.LastInsertId()
 }
diff --git a/database/gdb/gdb_type_result.go b/database/gdb/gdb_type_result.go
index b73711a87..cfbeff838 100644
--- a/database/gdb/gdb_type_result.go
+++ b/database/gdb/gdb_type_result.go
@@ -9,11 +9,33 @@ package gdb
 import (
 	"database/sql"
 	"fmt"
+	"math"
 	"reflect"
 
 	"github.com/gogf/gf/encoding/gparser"
 )
 
+// Chunk splits an Result into multiple Results,
+// the size of each array is determined by <size>.
+// The last chunk may contain less than size elements.
+func (r Result) Chunk(size int) []Result {
+	if size < 1 {
+		return nil
+	}
+	length := len(r)
+	chunks := int(math.Ceil(float64(length) / float64(size)))
+	var n []Result
+	for i, end := 0, 0; chunks > 0; chunks-- {
+		end = (i + 1) * size
+		if end > length {
+			end = length
+		}
+		n = append(n, r[i*size:end])
+		i++
+	}
+	return n
+}
+
 // Json converts <r> to JSON format content.
 func (r Result) Json() string {
 	content, _ := gparser.VarToJson(r.List())
diff --git a/database/gdb/gdb_unit_z_mysql_model_test.go b/database/gdb/gdb_unit_z_mysql_model_test.go
index 0e478e2c7..7f2032acf 100644
--- a/database/gdb/gdb_unit_z_mysql_model_test.go
+++ b/database/gdb/gdb_unit_z_mysql_model_test.go
@@ -2123,3 +2123,38 @@ func Test_Model_OmitEmpty_Time(t *testing.T) {
 		t.Assert(n, 1)
 	})
 }
+
+func Test_Result_Chunk(t *testing.T) {
+	table := createInitTable()
+	defer dropTable(table)
+	gtest.C(t, func(t *gtest.T) {
+		r, err := db.Table(table).Order("id asc").All()
+		t.Assert(err, nil)
+		chunks := r.Chunk(3)
+		t.Assert(len(chunks), 4)
+		t.Assert(chunks[0][0]["id"].Int(), 1)
+		t.Assert(chunks[1][0]["id"].Int(), 4)
+		t.Assert(chunks[2][0]["id"].Int(), 7)
+		t.Assert(chunks[3][0]["id"].Int(), 10)
+	})
+}
+
+func Test_Model_DryRun(t *testing.T) {
+	table := createInitTable()
+	defer dropTable(table)
+	db.SetDryRun(true)
+	defer db.SetDryRun(false)
+
+	gtest.C(t, func(t *gtest.T) {
+		one, err := db.Table(table).FindOne(1)
+		t.Assert(err, nil)
+		t.Assert(one["id"], 1)
+	})
+	gtest.C(t, func(t *gtest.T) {
+		r, err := db.Table(table).Data("passport", "port_1").WherePri(1).Update()
+		t.Assert(err, nil)
+		n, err := r.RowsAffected()
+		t.Assert(err, nil)
+		t.Assert(n, 0)
+	})
+}
diff --git a/net/ghttp/ghttp_client_request.go b/net/ghttp/ghttp_client_request.go
index 15a58eeaf..f3f793ff2 100644
--- a/net/ghttp/ghttp_client_request.go
+++ b/net/ghttp/ghttp_client_request.go
@@ -189,15 +189,9 @@ func (c *Client) DoRequest(method, url string, data ...interface{}) (resp *Clien
 			req.Header.Set(k, v)
 		}
 	}
-	// For server requests Host specifies the host on which the
-	// URL is sought. Per RFC 2616, this is either the value of
-	// the "Host" header or the host name given in the URL itself.
-	// It may be of the form "host:port".
-	//
-	// For client requests Host optionally overrides the Host
-	// header to send. If empty, the Request.Write method uses
-	// the value of URL.Host.
-	if host := req.Header.Get("Host"); host != "" {
+	// It's necessary set the req.Host if you want to custom the host value of the request.
+	// It uses the "Host" value of the header.
+	if host := req.Header.Get("Host"); host != "" && req.Host == "" {
 		req.Host = host
 	}
 	// Custom Cookie.
diff --git a/net/ghttp/ghttp_response_write.go b/net/ghttp/ghttp_response_write.go
index 9e8db6b1a..9c754c089 100644
--- a/net/ghttp/ghttp_response_write.go
+++ b/net/ghttp/ghttp_response_write.go
@@ -107,7 +107,7 @@ func (r *Response) WriteJson(content interface{}) error {
 	switch content.(type) {
 	case string, []byte:
 		r.Header().Set("Content-Type", "application/json")
-		r.Write(content)
+		r.Write(gconv.String(content))
 		return nil
 	}
 	// Else use json.Marshal function to encode the parameter.
@@ -139,7 +139,7 @@ func (r *Response) WriteJsonP(content interface{}) error {
 	switch content.(type) {
 	case string, []byte:
 		r.Header().Set("Content-Type", "application/json")
-		r.Write(content)
+		r.Write(gconv.String(content))
 		return nil
 	}
 	// Else use json.Marshal function to encode the parameter.
@@ -179,7 +179,7 @@ func (r *Response) WriteXml(content interface{}, rootTag ...string) error {
 	switch content.(type) {
 	case string, []byte:
 		r.Header().Set("Content-Type", "application/xml")
-		r.Write(content)
+		r.Write(gconv.String(content))
 		return nil
 	}
 	// Else use gparser.VarToXml function to encode the parameter.
diff --git a/os/genv/genv.go b/os/genv/genv.go
index 8ab463420..e8b2c183e 100644
--- a/os/genv/genv.go
+++ b/os/genv/genv.go
@@ -7,7 +7,10 @@
 // Package genv provides operations for environment variables of system.
 package genv
 
-import "os"
+import (
+	"github.com/gogf/gf/container/gvar"
+	"os"
+)
 import "strings"
 
 // All returns a copy of strings representing the environment,
@@ -37,6 +40,17 @@ func Get(key string, def ...string) string {
 	return v
 }
 
+// GetVar creates and returns a Var with the value of the environment variable
+// named by the <key>. It uses the given <def> if the variable does not exist
+// in the environment.
+func GetVar(key string, def ...interface{}) *gvar.Var {
+	v, ok := os.LookupEnv(key)
+	if !ok && len(def) > 0 {
+		return gvar.New(def[0])
+	}
+	return gvar.New(v)
+}
+
 // Set sets the value of the environment variable named by the <key>.
 // It returns an error, if any.
 func Set(key, value string) error {