diff --git a/models/login_source.go b/models/login_source.go
index 88ad42dc5..03d3af6d3 100644
--- a/models/login_source.go
+++ b/models/login_source.go
@@ -131,7 +131,7 @@ func (f *AuthSourceFile) Save() error {
 type LoginSource struct {
 	ID        int64
 	Type      LoginType
-	Name      string          `xorm:"UNIQUE"`
+	Name      string          `xorm:"varchar(191) UNIQUE"`
 	IsActived bool            `xorm:"NOT NULL DEFAULT false"`
 	Cfg       core.Conversion `xorm:"TEXT"`
 
diff --git a/models/models.go b/models/models.go
index 6407f4134..b80f9c36b 100644
--- a/models/models.go
+++ b/models/models.go
@@ -330,6 +330,7 @@ func ImportDatabase(dirPath string, verbose bool) (err error) {
 		rawTableName := x.TableName(table)
 		_, isInsertProcessor := table.(xorm.BeforeInsertProcessor)
 		scanner := bufio.NewScanner(f)
+
 		for scanner.Scan() {
 			switch bean := table.(type) {
 			case *LoginSource:
@@ -367,8 +368,11 @@ func ImportDatabase(dirPath string, verbose bool) (err error) {
 
 			// Reset created_unix back to the date save in archive because Insert method updates its value
 			if isInsertProcessor && !skipInsertProcessors[rawTableName] {
-				if _, err = x.Exec("UPDATE "+rawTableName+" SET created_unix=? WHERE id=?", meta["CreatedUnix"], meta["ID"]); err != nil {
-					log.Error(2, "Failed to reset 'created_unix': %v", err)
+				timestamp, ok := meta["CreatedUnix"].(uint64)
+				if ok {
+					if _, err = x.Exec("UPDATE "+rawTableName+" SET created_unix=? WHERE id=?", timestamp, meta["ID"]); err != nil {
+						log.Error(2, "Failed to reset 'created_unix': %v", err)
+					}
 				}
 			}
 
diff --git a/models/repo.go b/models/repo.go
index c9c1964ae..68659d653 100644
--- a/models/repo.go
+++ b/models/repo.go
@@ -152,7 +152,7 @@ type Repository struct {
 	ID              int64
 	OwnerID         int64  `xorm:"UNIQUE(s)"`
 	Owner           *User  `xorm:"-" json:"-"`
-	LowerName       string `xorm:"UNIQUE(s) INDEX NOT NULL"`
+	LowerName       string `xorm:"varchar(191) UNIQUE(s) INDEX NOT NULL"`
 	Name            string `xorm:"INDEX NOT NULL"`
 	Description     string `xorm:"VARCHAR(512)"`
 	Website         string
diff --git a/models/repo_branch.go b/models/repo_branch.go
index 1d98fd12a..b080d8c5a 100644
--- a/models/repo_branch.go
+++ b/models/repo_branch.go
@@ -70,7 +70,7 @@ type ProtectBranchWhitelist struct {
 	ID              int64
 	ProtectBranchID int64
 	RepoID          int64  `xorm:"UNIQUE(protect_branch_whitelist)"`
-	Name            string `xorm:"UNIQUE(protect_branch_whitelist)"`
+	Name            string `xorm:"varchar(191) UNIQUE(protect_branch_whitelist)"`
 	UserID          int64  `xorm:"UNIQUE(protect_branch_whitelist)"`
 }
 
@@ -84,7 +84,7 @@ func IsUserInProtectBranchWhitelist(repoID, userID int64, branch string) bool {
 type ProtectBranch struct {
 	ID                 int64
 	RepoID             int64  `xorm:"UNIQUE(protect_branch)"`
-	Name               string `xorm:"UNIQUE(protect_branch)"`
+	Name               string `xorm:"varchar(191) UNIQUE(protect_branch)"`
 	Protected          bool
 	RequirePullRequest bool
 	EnableWhitelist    bool
diff --git a/models/user.go b/models/user.go
index 7e014df43..6e7eda319 100644
--- a/models/user.go
+++ b/models/user.go
@@ -48,8 +48,8 @@ const (
 // User represents the object of individual and member of organization.
 type User struct {
 	ID        int64
-	LowerName string `xorm:"UNIQUE NOT NULL"`
-	Name      string `xorm:"UNIQUE NOT NULL"`
+	LowerName string `xorm:"varchar(191) UNIQUE NOT NULL"`
+	Name      string `xorm:"varchar(191) UNIQUE NOT NULL"`
 	FullName  string
 	// Email is the primary email address (to be used for communication)
 	Email       string `xorm:"NOT NULL"`
diff --git a/models/user_mail.go b/models/user_mail.go
index 46197490f..2231c000c 100644
--- a/models/user_mail.go
+++ b/models/user_mail.go
@@ -16,7 +16,7 @@ import (
 type EmailAddress struct {
 	ID          int64
 	UID         int64  `xorm:"INDEX NOT NULL"`
-	Email       string `xorm:"UNIQUE NOT NULL"`
+	Email       string `xorm:"varchar(191) UNIQUE NOT NULL"`
 	IsActivated bool
 	IsPrimary   bool `xorm:"-" json:"-"`
 }