Refactor parsing & select order by impl (#6)

Reviewed-on: #6

schema/table.go

@@ -1,23 +1,47 @@
 package schema
 
 import (
+	"errors"
 	"reflect"
 	"strings"
 
 	"git.gdulai.com/gdulai/simpleorm/util"
 )
 
+type OrderBy struct {
+	Field     string
+	Direction string
+}
+
 type Table struct {
-	Name        string
-	Type        reflect.Type
-	Columns     []Column
-	Constraints []Constraint
+	name        string
+	typ         reflect.Type
+	columns     []Column
+	constraints []Constraint
+}
+
+func (t Table) Name() string {
+	return t.name
+}
+
+func (t Table) Type() reflect.Type {
+	return t.typ
+}
+
+func (t Table) Columns() []Column {
+	return t.columns
+}
+
+func (t Table) Constraints() []Constraint {
+	return t.constraints
 }
 
 func (t Table) GetDDL() (string, error) {
 	var ddl strings.Builder
-	ddl.WriteString("CREATE TABLE IF NOT EXISTS " + t.Name + " (")
-	for i, col := range t.Columns {
+	ddl.WriteString("CREATE TABLE IF NOT EXISTS ")
+	ddl.WriteString(t.name)
+	ddl.WriteString(" (")
+	for i, col := range t.columns {
 		if i != 0 {
 			ddl.WriteString(", ")
 		}
@@ -27,12 +51,13 @@ func (t Table) GetDDL() (string, error) {
 		}
 		ddl.WriteString(colDdl)
 	}
-	for _, constr := range t.Constraints {
+	for _, constr := range t.constraints {
 		constrDdl, err := constr.GetDDL()
 		if err != nil {
 			return "", err
 		}
-		ddl.WriteString(", " + constrDdl)
+		ddl.WriteString(", ")
+		ddl.WriteString(constrDdl)
 	}
 
 	ddl.WriteString(");")
@@ -43,7 +68,7 @@ func (t Table) GetSelectDML() (string, error) {
 	var dml strings.Builder
 	dml.WriteString("SELECT ")
 
-	for i, col := range t.Columns {
+	for i, col := range t.columns {
 		if i != 0 {
 			dml.WriteString(", ")
 		}
@@ -54,21 +79,24 @@ func (t Table) GetSelectDML() (string, error) {
 		dml.WriteString(colDml)
 	}
 
-	dml.WriteString(" FROM " + t.Name)
+	dml.WriteString(" FROM ")
+	dml.WriteString(t.name)
 	return dml.String(), nil
 }
 
 func (t Table) GetCountDML() string {
-	return "SELECT COUNT(*) FROM " + t.Name
+	return "SELECT COUNT(*) FROM " + t.name
 }
 
 func (t Table) GetInsertDML(count int) (string, error) {
 	var dml strings.Builder
-	dml.WriteString("INSERT INTO " + util.CamelToSnake(t.Type.Name()) + " (")
+	dml.WriteString("INSERT INTO ")
+	dml.WriteString(util.CamelToSnake(t.typ.Name()))
+	dml.WriteString(" (")
 
-	columnsLen := len(t.Columns)
+	columnsLen := len(t.columns)
 	effectiveColumnsLen := 0
-	for i, col := range t.Columns {
+	for i, col := range t.columns {
 		_, ok := col.Modifiers["pk"]
 		if ok && t.IsPkAuto() {
 			continue
@@ -111,12 +139,14 @@ func (t Table) GetInsertDML(count int) (string, error) {
 
 func (t Table) GetUpdateDML() (string, error) {
 	var dml strings.Builder
-	dml.WriteString("UPDATE  " + util.CamelToSnake(t.Type.Name()) + " SET ")
+	dml.WriteString("UPDATE  ")
+	dml.WriteString(util.CamelToSnake(t.typ.Name()))
+	dml.WriteString(" SET ")
 
-	colLen := len(t.Columns)
+	colLen := len(t.columns)
 	var pkColumns []string
 	// Colum names
-	for i, col := range t.Columns {
+	for i, col := range t.columns {
 		modifiers := col.Modifiers
 
 		_, ok := modifiers["pk"]
@@ -133,9 +163,11 @@ func (t Table) GetUpdateDML() (string, error) {
 		}
 
 		if i != colLen-1 {
-			dml.WriteString(colDml + ", ")
+			dml.WriteString(colDml)
+			dml.WriteString(", ")
 		} else {
-			dml.WriteString(colDml + " ")
+			dml.WriteString(colDml)
+			dml.WriteString(" ")
 		}
 	}
 
@@ -145,7 +177,8 @@ func (t Table) GetUpdateDML() (string, error) {
 		if i != 0 {
 			dml.WriteString(" AND ")
 		}
-		dml.WriteString(pkCol + " = ?")
+		dml.WriteString(pkCol)
+		dml.WriteString(" = ?")
 	}
 
 	return dml.String(), nil
@@ -153,17 +186,21 @@ func (t Table) GetUpdateDML() (string, error) {
 
 func (t Table) GetDeleteDML(count int) (string, error) {
 	var dml strings.Builder
-	dml.WriteString("DELETE FROM " + t.Name + " WHERE ")
+	dml.WriteString("DELETE FROM ")
+	dml.WriteString(t.name)
+	dml.WriteString(" WHERE ")
 
-	for _, col := range t.Columns {
+	for _, col := range t.columns {
 		modifiers := col.Modifiers
 
 		_, ok := modifiers["pk"]
 		if ok {
 			if count > 1 {
-				dml.WriteString(col.Name + " IN (")
+				dml.WriteString(col.Name)
+				dml.WriteString(" IN (")
 			} else {
-				dml.WriteString(col.Name + " = ")
+				dml.WriteString(col.Name)
+				dml.WriteString(" = ")
 			}
 		}
 	}
@@ -182,8 +219,33 @@ func (t Table) GetDeleteDML(count int) (string, error) {
 	return dml.String(), nil
 }
 
+func (t Table) GetOrderByDML(ordering ...OrderBy) (string, error) {
+	var dml strings.Builder
+	dml.WriteString(" ORDER BY")
+	for _, orderBy := range ordering {
+		col, err := t.getColumnByField(orderBy.Field)
+		if err != nil {
+			return "", err
+		}
+		dml.WriteString(" ")
+		dml.WriteString(col.Name)
+		dml.WriteString(" ")
+		dml.WriteString(orderBy.Direction)
+	}
+	return dml.String(), nil
+}
+
+func (t Table) getColumnByField(fieldName string) (Column, error) {
+	for _, col := range t.columns {
+		if col.FieldName == fieldName {
+			return col, nil
+		}
+	}
+	return Column{}, errors.New("No column for field " + fieldName + " in table " + t.name)
+}
+
 func (t Table) IsPkAuto() bool {
-	for _, constr := range t.Constraints {
+	for _, constr := range t.constraints {
 		if constr.Type != "pk" {
 			continue
 		}