Refactoring to support parameterized queries.

sqlbuilder/utils.go

@@ -1,19 +1,20 @@
 package sqlbuilder
 
 import (
-	"bytes"
 	"database/sql"
+	"errors"
 	"github.com/sub0zero/go-sqlbuilder/sqlbuilder/execution"
 	"github.com/sub0zero/go-sqlbuilder/types"
 )
 
-func serializeExpressionList(expressions []Expression, buf *bytes.Buffer) error {
-	for i, value := range expressions {
+func serializeOrderByClauseList(orderByClauses []OrderByClause, out *queryData) error {
+
+	for i, value := range orderByClauses {
 		if i > 0 {
-			buf.WriteString(", ")
+			out.WriteString(", ")
 		}
 
-		err := value.SerializeSql(buf)
+		err := value.Serialize(out)
 
 		if err != nil {
 			return err
@@ -23,13 +24,33 @@ func serializeExpressionList(expressions []Expression, buf *bytes.Buffer) error
 	return nil
 }
 
-func serializeProjectionList(projections []Projection, buf *bytes.Buffer) error {
-	for i, value := range projections {
+func serializeClauseList(clauses []Clause, out *queryData) (err error) {
+
+	for i, c := range clauses {
 		if i > 0 {
-			buf.WriteString(", ")
+			out.WriteString(", ")
 		}
 
-		err := value.SerializeForProjection(buf)
+		if c == nil {
+			return errors.New("nil clause.")
+		}
+
+		if err = c.Serialize(out); err != nil {
+			return
+		}
+	}
+
+	return nil
+}
+
+func serializeExpressionList(expressions []Expression, separator string, out *queryData) error {
+
+	for i, value := range expressions {
+		if i > 0 {
+			out.WriteString(separator)
+		}
+
+		err := value.Serialize(out)
 
 		if err != nil {
 			return err
@@ -39,24 +60,55 @@ func serializeProjectionList(projections []Projection, buf *bytes.Buffer) error
 	return nil
 }
 
+func serializeProjectionList(projections []Projection, out *queryData) error {
+	for i, col := range projections {
+		if i > 0 {
+			out.WriteByte(',')
+		}
+		if col == nil {
+			return errors.New("Projection expression is nil.")
+		}
+
+		if err := col.SerializeForProjection(out); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func serializeColumnList(columns []Column, out *queryData) error {
+	for i, col := range columns {
+		if i > 0 {
+			out.WriteByte(',')
+		}
+
+		if col == nil {
+			return errors.New("nil column in columns list.")
+		}
+
+		out.WriteString(col.Name())
+	}
+
+	return nil
+}
+
 func Query(statement Statement, db types.Db, destination interface{}) error {
-	query, err := statement.String()
+	query, args, err := statement.Sql()
 
 	if err != nil {
 		return err
 	}
 
-	return execution.Execute(db, query, destination)
+	return execution.Query(db, query, args, destination)
 }
 
 func Execute(statement Statement, db types.Db) (res sql.Result, err error) {
-	query, err := statement.String()
+	query, args, err := statement.Sql()
 
 	if err != nil {
 		return
 	}
 
-	res, err = db.Exec(query)
-
-	return
+	return db.Exec(query, args...)
 }