Named queries

dbc/named.go

@@ -3,10 +3,37 @@ package dbc
 import (
 	"fmt"
 	"reflect"
+	"regexp"
+	"strings"
 
 	"github.com/localhots/gobelt/reflect2"
 )
 
+var namedRegexp = regexp.MustCompile("" +
+	"`[^`]+`|" +
+	`'[^']+'|` +
+	`"[^"]+"|` +
+	`@[a-zA-Z][a-zA-Z0-9_]*`)
+
+func prepareNamedQuery(query string, p namedParams) (newQuery string, args []interface{}, err error) {
+	newQuery = namedRegexp.ReplaceAllStringFunc(query, func(m string) string {
+		if !strings.HasPrefix(m, "@") {
+			return m
+		}
+		val, ok := p.Get(m[1:])
+		if !ok {
+			err = fmt.Errorf("Named parameter %s was not found", m)
+		}
+		args = append(args, val)
+		return "?"
+	})
+	return
+}
+
+//
+// Params
+//
+
 type namedParams interface {
 	Get(name string) (val interface{}, ok bool)
 }
@@ -58,9 +85,8 @@ func newNamedParamsStruct(s interface{}) (*namedParamsStruct, error) {
 }
 
 func (p *namedParamsStruct) Get(name string) (val interface{}, ok bool) {
-	i, ok := p.idx[name]
-	if !ok {
-		return nil, false
+	if i, ok := p.idx[name]; ok {
+		return p.s.Field(i).Interface(), true
 	}
-	return p.s.Field(i).Interface(), true
+	return nil, false
 }

dbc/named_test.go

@@ -1,6 +1,32 @@
 package dbc
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestPrepareNamedQuery(t *testing.T) {
+	q := `SELECT id, "@not_param ", '@name', "i", ` + "`password` " +
+		`FROM tbl WHERE name = @name, active = @is_active`
+	p, err := newNamedParamsMap(map[string]interface{}{"name": "Bob", "is_active": 1})
+	if err != nil {
+		t.Fatalf("Failed to create named params map: %v", err)
+	}
+	q, args, err := prepareNamedQuery(q, p)
+	if err != nil {
+		t.Fatalf("Failed to prepare named statement: %v", err)
+	}
+	const expQ = `SELECT id, "@not_param ", '@name', "i", ` + "`password` " +
+		`FROM tbl WHERE name = ?, active = ?`
+	if q != expQ {
+		t.Errorf("Expected query to be\n%s\ngot\n%q", expQ, q)
+	}
+	expA := []interface{}{"Bob", 1}
+	if !cmp.Equal(expA, args) {
+		t.Errorf("Returned arguments are different: %s", cmp.Diff(expA, args))
+	}
+}
 
 func TestNamedParamsMap(t *testing.T) {
 	m, err := newNamedParamsMap(map[string]interface{}{
@@ -55,9 +81,9 @@ func BenchmarkNamedParamsMap(b *testing.B) {
 	if err != nil {
 		b.Fatalf("Failed to create named params map: %v", err)
 	}
+
 	b.ReportAllocs()
 	b.ResetTimer()
-
 	for i := 0; i < b.N; i++ {
 		m.Get("foo")
 	}
@@ -71,10 +97,40 @@ func BenchmarkNamedParamsStruct(b *testing.B) {
 	if err != nil {
 		b.Fatalf("Failed to create named params struct: %v", err)
 	}
+
 	b.ReportAllocs()
 	b.ResetTimer()
-
 	for i := 0; i < b.N; i++ {
 		m.Get("foo")
 	}
 }
+
+func BenchmarkPrepareNamedOne(b *testing.B) {
+	p, _ := newNamedParamsMap(map[string]interface{}{
+		"name": "Bob",
+	})
+	const q = `SELECT * FROM tbl WHER name = @name`
+
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		prepareNamedQuery(q, p)
+	}
+}
+
+func BenchmarkPrepareNamedQuerySix(b *testing.B) {
+	p, _ := newNamedParamsMap(map[string]interface{}{
+		"name":      "Bob",
+		"is_active": 1,
+		"amount":    123.45,
+	})
+	const q = `SELECT "aaa @false1 bbb" as f1, 'ccc @false2 ddd' as f2, ` +
+		"`eee @false3 fff` as f3, name, is_active, amount FROM tbl " +
+		`WHERE name = @name AND is_active = @is_active AND amount = @amount`
+
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		prepareNamedQuery(q, p)
+	}
+}

dbc/query.go

@@ -48,7 +48,15 @@ func (c *caller) Exec(ctx context.Context, query string, args ...interface{}) Ex
 }
 
 func (c *caller) ExecNamed(ctx context.Context, query string, arg interface{}) ExecResult {
-	return nil
+	params, err := newNamedParams(arg)
+	if err != nil {
+		return &execResult{err: err}
+	}
+	preparedQuery, args, err := prepareNamedQuery(query, params)
+	if err != nil {
+		return &execResult{err: err}
+	}
+	return c.Exec(ctx, preparedQuery, args...)
 }
 
 func (c *caller) Query(ctx context.Context, query string, args ...interface{}) Rows {
@@ -63,5 +71,13 @@ func (c *caller) Query(ctx context.Context, query string, args ...interface{}) R
 }
 
 func (c *caller) QueryNamed(ctx context.Context, query string, arg interface{}) Rows {
-	return nil
+	params, err := newNamedParams(arg)
+	if err != nil {
+		return &rows{err: err}
+	}
+	preparedQuery, args, err := prepareNamedQuery(query, params)
+	if err != nil {
+		return &rows{err: err}
+	}
+	return c.Query(ctx, preparedQuery, args...)
 }