diff --git a/dialect_mysql.go b/dialect_mysql.go
index 06606b8b..b70617a2 100644
--- a/dialect_mysql.go
+++ b/dialect_mysql.go
@@ -26,11 +26,19 @@ type MySQLDialect struct {
 
 	// Encoding is the character encoding to use for created tables
 	Encoding string
+
+	// TypeMap overrides the default column types
+	TypeMap map[reflect.Type]string
 }
 
 func (d MySQLDialect) QuerySuffix() string { return ";" }
 
 func (d MySQLDialect) ToSqlType(val reflect.Type, maxsize int, isAutoIncr bool) string {
+	if d.TypeMap != nil {
+		if typ, ok := d.TypeMap[val]; ok {
+			return typ
+		}
+	}
 	switch val.Kind() {
 	case reflect.Ptr:
 		return d.ToSqlType(val.Elem(), maxsize, isAutoIncr)
diff --git a/dialect_mysql_test.go b/dialect_mysql_test.go
index 9acfee35..b37b0fdc 100644
--- a/dialect_mysql_test.go
+++ b/dialect_mysql_test.go
@@ -30,10 +30,15 @@ var _ = Describe("MySQLDialect", func() {
 		dialect          gorp.MySQLDialect
 	)
 
+	type IntAsBool int
+
 	JustBeforeEach(func() {
 		dialect = gorp.MySQLDialect{
 			Engine:   engine,
 			Encoding: encoding,
+			TypeMap: map[reflect.Type]string{
+				reflect.TypeOf(IntAsBool(0)): "boolean",
+			},
 		}
 	})
 
@@ -64,6 +69,7 @@ var _ = Describe("MySQLDialect", func() {
 		Entry("default-size string", "", 0, false, "varchar(255)"),
 		Entry("sized string", "", 50, false, "varchar(50)"),
 		Entry("large string", "", 1024, false, "text"),
+		Entry("custome type map", IntAsBool(1), 0, false, "boolean"),
 	)
 
 	Describe("AutoIncrStr", func() {
diff --git a/dialect_oracle.go b/dialect_oracle.go
index c381380f..d3945e4f 100644
--- a/dialect_oracle.go
+++ b/dialect_oracle.go
@@ -18,7 +18,11 @@ import (
 )
 
 // Implementation of Dialect for Oracle databases.
-type OracleDialect struct{}
+type OracleDialect struct {
+
+	// TypeMap overrides the default column types
+	TypeMap map[reflect.Type]string
+}
 
 func (d OracleDialect) QuerySuffix() string { return "" }
 
@@ -27,6 +31,11 @@ func (d OracleDialect) CreateIndexSuffix() string { return "" }
 func (d OracleDialect) DropIndexSuffix() string { return "" }
 
 func (d OracleDialect) ToSqlType(val reflect.Type, maxsize int, isAutoIncr bool) string {
+	if d.TypeMap != nil {
+		if typ, ok := d.TypeMap[val]; ok {
+			return typ
+		}
+	}
 	switch val.Kind() {
 	case reflect.Ptr:
 		return d.ToSqlType(val.Elem(), maxsize, isAutoIncr)
diff --git a/dialect_postgres.go b/dialect_postgres.go
index a53973cd..35ac0b20 100644
--- a/dialect_postgres.go
+++ b/dialect_postgres.go
@@ -20,11 +20,19 @@ import (
 
 type PostgresDialect struct {
 	suffix string
+
+	// TypeMap overrides the default column types
+	TypeMap map[reflect.Type]string
 }
 
 func (d PostgresDialect) QuerySuffix() string { return ";" }
 
 func (d PostgresDialect) ToSqlType(val reflect.Type, maxsize int, isAutoIncr bool) string {
+	if d.TypeMap != nil {
+		if typ, ok := d.TypeMap[val]; ok {
+			return typ
+		}
+	}
 	switch val.Kind() {
 	case reflect.Ptr:
 		return d.ToSqlType(val.Elem(), maxsize, isAutoIncr)
diff --git a/dialect_sqlite.go b/dialect_sqlite.go
index 7d9b2975..82f36962 100644
--- a/dialect_sqlite.go
+++ b/dialect_sqlite.go
@@ -18,11 +18,19 @@ import (
 
 type SqliteDialect struct {
 	suffix string
+
+	// TypeMap overrides the default column types
+	TypeMap map[reflect.Type]string
 }
 
 func (d SqliteDialect) QuerySuffix() string { return ";" }
 
 func (d SqliteDialect) ToSqlType(val reflect.Type, maxsize int, isAutoIncr bool) string {
+	if d.TypeMap != nil {
+		if typ, ok := d.TypeMap[val]; ok {
+			return typ
+		}
+	}
 	switch val.Kind() {
 	case reflect.Ptr:
 		return d.ToSqlType(val.Elem(), maxsize, isAutoIncr)
diff --git a/dialect_sqlserver.go b/dialect_sqlserver.go
index 8808af59..5033aee0 100644
--- a/dialect_sqlserver.go
+++ b/dialect_sqlserver.go
@@ -25,9 +25,17 @@ type SqlServerDialect struct {
 
 	// If set to "2005" legacy datatypes will be used
 	Version string
+
+	// TypeMap overrides the default column types
+	TypeMap map[reflect.Type]string
 }
 
 func (d SqlServerDialect) ToSqlType(val reflect.Type, maxsize int, isAutoIncr bool) string {
+	if d.TypeMap != nil {
+		if typ, ok := d.TypeMap[val]; ok {
+			return typ
+		}
+	}
 	switch val.Kind() {
 	case reflect.Ptr:
 		return d.ToSqlType(val.Elem(), maxsize, isAutoIncr)
diff --git a/gorp_test.go b/gorp_test.go
index 98ea4d3e..a2a0e7f8 100644
--- a/gorp_test.go
+++ b/gorp_test.go
@@ -2557,9 +2557,9 @@ func connect(driver string) *sql.DB {
 func dialectAndDriver() (gorp.Dialect, string) {
 	switch os.Getenv("GORP_TEST_DIALECT") {
 	case "mysql":
-		return gorp.MySQLDialect{"InnoDB", "UTF8"}, "mymysql"
+		return gorp.MySQLDialect{"InnoDB", "UTF8", nil}, "mymysql"
 	case "gomysql":
-		return gorp.MySQLDialect{"InnoDB", "UTF8"}, "mysql"
+		return gorp.MySQLDialect{"InnoDB", "UTF8", nil}, "mysql"
 	case "postgres":
 		return gorp.PostgresDialect{}, "postgres"
 	case "sqlite":