queryx: added Get, GetRelease, Select and SelectRelease helper functions

I have piggy backed with this change some docs update.

Fixes #41

README.md

@@ -29,9 +29,9 @@ type Person struct {
     Email     []string
 }
 
-// Insert with query parameters bound from struct.
+// Bind query parameters from a struct.
 {
-    p := &Person{
+    p := Person{
         "Patricia",
         "Citizen",
         []string{"patricia.citzen@gocqlx_test.com"},
@@ -41,49 +41,42 @@ type Person struct {
         Columns("first_name", "last_name", "email").
         ToCql()
 
-    q := gocqlx.Query(session.Query(stmt), names).BindStruct(p)
+    err := gocqlx.Query(session.Query(stmt), names).BindStruct(&p).ExecRelease()
-
+    if err != nil {
-    if err := q.ExecRelease(); err != nil {
         t.Fatal(err)
     }
 }
 
-// Get the first result into a struct.
+// Load the first result into a struct.
 {
     stmt, names := qb.Select("gocqlx_test.person").
         Where(qb.Eq("first_name")).
         ToCql()
 
+    var p Person
+
     q := gocqlx.Query(session.Query(stmt), names).BindMap(qb.M{
         "first_name": "Patricia",
     })
-
+    if err := q.GetRelease(&p); err != nil {
-    var p Person
+        t.Fatal(err)
-    if err := gocqlx.Get(&p, q.Query); err != nil {
-        t.Fatal("get:", err)
     }
-
-    t.Log(p)
-    // {Patricia Citizen [patricia.citzen@gocqlx_test.com patricia1.citzen@gocqlx_test.com]}
 }
 
-// Select, load all the results into a slice.
+// Load all the results into a slice.
 {
     stmt, names := qb.Select("gocqlx_test.person").
         Where(qb.In("first_name")).
         ToCql()
 
+    var people []Person
+
     q := gocqlx.Query(session.Query(stmt), names).BindMap(qb.M{
         "first_name": []string{"Patricia", "Igy", "Ian"},
     })
-
+    if err := q.SelectRelease(&people); err != nil {
-    var people []Person
+        t.Fatal(err)
-    if err := gocqlx.Select(&people, q.Query); err != nil {
-        t.Fatal("select:", err)
     }
-
-    t.Log(people)
-    // [{Patricia Citizen [patricia.citzen@gocqlx_test.com patricia1.citzen@gocqlx_test.com]} {Igy Citizen [igy.citzen@gocqlx_test.com]} {Ian Citizen [ian.citzen@gocqlx_test.com]}]
 }
 ```
 

example_test.go

@@ -38,26 +38,25 @@ func TestExample(t *testing.T) {
 		t.Fatal("create table:", err)
 	}
 
-	p := &Person{
+	p := Person{
 		"Patricia",
 		"Citizen",
 		[]string{"patricia.citzen@gocqlx_test.com"},
 	}
 
-	// Insert with query parameters bound from struct.
+	// Bind query parameters from struct.
 	{
 		stmt, names := qb.Insert("gocqlx_test.person").
 			Columns("first_name", "last_name", "email").
 			ToCql()
 
-		q := gocqlx.Query(session.Query(stmt), names).BindStruct(p)
+		err := gocqlx.Query(session.Query(stmt), names).BindStruct(&p).ExecRelease()
-
+		if err != nil {
-		if err := q.ExecRelease(); err != nil {
 			t.Fatal(err)
 		}
 	}
 
-	// Insert with query parameters bound from struct extended with a map.
+	// Bind query parameters from struct and map.
 	{
 		stmt, names := qb.Insert("gocqlx_test.person").
 			Columns("first_name", "last_name", "email").
@@ -67,13 +66,12 @@ func TestExample(t *testing.T) {
 		q := gocqlx.Query(session.Query(stmt), names).BindStructMap(p, qb.M{
 			"_ttl": qb.TTL(86400 * time.Second),
 		})
-
 		if err := q.ExecRelease(); err != nil {
 			t.Fatal(err)
 		}
 	}
 
-	// Easy update with all parameters bound from struct.
+	// Update with query parameters from struct.
 	{
 		p.Email = append(p.Email, "patricia1.citzen@gocqlx_test.com")
 
@@ -82,14 +80,13 @@ func TestExample(t *testing.T) {
 			Where(qb.Eq("first_name"), qb.Eq("last_name")).
 			ToCql()
 
-		q := gocqlx.Query(session.Query(stmt), names).BindStruct(p)
+		err := gocqlx.Query(session.Query(stmt), names).BindStruct(p).ExecRelease()
-
+		if err != nil {
-		if err := q.ExecRelease(); err != nil {
 			t.Fatal(err)
 		}
 	}
 
-	// Advanced update, adding and removing elements to collections and counters.
+	// Adding and removing elements to collections and counters.
 	{
 		stmt, names := qb.Update("gocqlx_test.person").
 			AddNamed("email", "new_email").
@@ -99,13 +96,12 @@ func TestExample(t *testing.T) {
 		q := gocqlx.Query(session.Query(stmt), names).BindStructMap(p, qb.M{
 			"new_email": []string{"patricia2.citzen@gocqlx_test.com", "patricia3.citzen@gocqlx_test.com"},
 		})
-
 		if err := q.ExecRelease(); err != nil {
 			t.Fatal(err)
 		}
 	}
 
-	// Batch insert two rows in a single query, advanced struct binding.
+	// Batch insert two rows in a single query.
 	{
 		i := qb.Insert("gocqlx_test.person").Columns("first_name", "last_name", "email")
 
@@ -130,54 +126,51 @@ func TestExample(t *testing.T) {
 			},
 		}
 
-		q := gocqlx.Query(session.Query(stmt), names).BindStruct(&batch)
+		err := gocqlx.Query(session.Query(stmt), names).BindStruct(&batch).ExecRelease()
-
+		if err != nil {
-		if err := q.ExecRelease(); err != nil {
 			t.Fatal(err)
 		}
 	}
 
-	// Get the first result into a struct.
+	// Load the first result into a struct.
 	{
 		stmt, names := qb.Select("gocqlx_test.person").
 			Where(qb.Eq("first_name")).
 			ToCql()
 
+		var p Person
+
 		q := gocqlx.Query(session.Query(stmt), names).BindMap(qb.M{
 			"first_name": "Patricia",
 		})
-		defer q.Release()
+		if err := q.GetRelease(&p); err != nil {
-
+			t.Fatal(err)
-		var p Person
-		if err := gocqlx.Get(&p, q.Query); err != nil {
-			t.Fatal("get:", err)
 		}
 
 		t.Log(p)
 		// {Patricia Citizen [patricia.citzen@gocqlx_test.com patricia1.citzen@gocqlx_test.com patricia2.citzen@gocqlx_test.com patricia3.citzen@gocqlx_test.com]}
 	}
 
-	// Select, load all the results into a slice.
+	// Load all the results into a slice.
 	{
 		stmt, names := qb.Select("gocqlx_test.person").
 			Where(qb.In("first_name")).
 			ToCql()
 
+		var people []Person
+
 		q := gocqlx.Query(session.Query(stmt), names).BindMap(qb.M{
 			"first_name": []string{"Patricia", "Igy", "Ian"},
 		})
-		defer q.Release()
+		if err := q.SelectRelease(&people); err != nil {
-
+			t.Fatal(err)
-		var people []Person
-		if err := gocqlx.Select(&people, q.Query); err != nil {
-			t.Fatal("select:", err)
 		}
 
 		t.Log(people)
 		// [{Ian Citizen [ian.citzen@gocqlx_test.com]} {Igy Citizen [igy.citzen@gocqlx_test.com]} {Patricia Citizen [patricia.citzen@gocqlx_test.com patricia1.citzen@gocqlx_test.com patricia2.citzen@gocqlx_test.com patricia3.citzen@gocqlx_test.com]}]
 	}
 
-	// Easy token based pagination.
+	// Token based pagination.
 	{
 		p := &Person{
 			"Ian",
@@ -191,12 +184,11 @@ func TestExample(t *testing.T) {
 			Limit(10).
 			ToCql()
 
-		q := gocqlx.Query(session.Query(stmt), names).BindStruct(p)
-		defer q.Release()
-
 		var people []Person
-		if err := gocqlx.Select(&people, q.Query); err != nil {
+
-			t.Fatal("select:", err)
+		err := gocqlx.Query(session.Query(stmt), names).BindStruct(p).SelectRelease(&people)
+		if err != nil {
+			t.Fatal(err)
 		}
 
 		t.Log(people)
@@ -213,12 +205,11 @@ func TestExample(t *testing.T) {
 
 		stmt, names, err := gocqlx.CompileNamedQuery([]byte("INSERT INTO gocqlx_test.person (first_name, last_name, email) VALUES (:first_name, :last_name, :email)"))
 		if err != nil {
-			t.Fatal("compile:", err)
+			t.Fatal(err)
 		}
 
-		q := gocqlx.Query(session.Query(stmt), names).BindStruct(p)
+		err = gocqlx.Query(session.Query(stmt), names).BindStruct(p).ExecRelease()
-
+		if err != nil {
-		if err := q.ExecRelease(); err != nil {
 			t.Fatal(err)
 		}
 	}

iterx.go

@@ -14,11 +14,15 @@ import (
 )
 
 // Get is a convenience function for creating iterator and calling Get.
+//
+// DEPRECATED use Queryx.Get or Queryx.GetRelease.
 func Get(dest interface{}, q *gocql.Query) error {
 	return Iter(q).Get(dest)
 }
 
 // Select is a convenience function for creating iterator and calling Select.
+//
+// DEPRECATED use Queryx.Select or Queryx.SelectRelease.
 func Select(dest interface{}, q *gocql.Query) error {
 	return Iter(q).Select(dest)
 }
@@ -53,9 +57,11 @@ func (iter *Iterx) Unsafe() *Iterx {
 }
 
 // Get scans first row into a destination and closes the iterator. If the
-// destination type is a Struct, then StructScan will be used. If the
+// destination type is a struct pointer, then StructScan will be used.
-// destination is some other type, then the row must only have one column which
+// If the destination is some other type, then the row must only have one column
-// can scan into that type. If no rows were selected, ErrNotFound is returned.
+// which can scan into that type.
+//
+// If no rows were selected, ErrNotFound is returned.
 func (iter *Iterx) Get(dest interface{}) error {
 	iter.scanAny(dest, false)
 	iter.Close()
@@ -99,10 +105,13 @@ func (iter *Iterx) scanAny(dest interface{}, structOnly bool) bool {
 	return iter.StructScan(dest)
 }
 
-// Select scans all rows into a destination, which must be a slice of any type
+// Select scans all rows into a destination, which must be a pointer to slice
-// and closes the iterator. If the destination slice type is a Struct, then
+// of any type and closes the iterator. If the destination slice type is
-// StructScan will be used on each row. If the destination is some other type,
+// a struct, then StructScan will be used on each row. If the destination is
-// then each row must only have one column which can scan into that type.
+// some other type, then each row must only have one column which can scan into
+// that type.
+//
+// If no rows were selected, ErrNotFound is NOT returned.
 func (iter *Iterx) Select(dest interface{}) error {
 	iter.scanAll(dest, false)
 	iter.Close()
@@ -191,7 +200,7 @@ func (iter *Iterx) scanAll(dest interface{}, structOnly bool) bool {
 }
 
 // StructScan is like gocql.Iter.Scan, but scans a single row into a single
-// Struct. Use this and iterate manually when the memory load of Select() might
+// struct. Use this and iterate manually when the memory load of Select() might
 // be prohibitive. StructScan caches the reflect work of matching up column
 // positions to fields to avoid that overhead per scan, which means it is not
 // safe to run StructScan on the same Iterx instance with different struct

queryx.go

@@ -191,9 +191,49 @@ func (q *Queryx) Exec() error {
 	return q.Query.Exec()
 }
 
-// ExecRelease performs exec and releases the query, a released query cannot be
+// ExecRelease calls Exec and releases the query, a released query cannot be
 // reused.
 func (q *Queryx) ExecRelease() error {
 	defer q.Release()
 	return q.Exec()
 }
+
+// Get scans first row into a destination. If the destination type is a struct
+// pointer, then Iter.StructScan will be used. If the destination is some
+// other type, then the row must only have one column which can scan into that
+// type.
+//
+// If no rows were selected, ErrNotFound is returned.
+func (q *Queryx) Get(dest interface{}) error {
+	if q.err != nil {
+		return q.err
+	}
+	return Iter(q.Query).Get(dest)
+}
+
+// GetRelease calls Get and releases the query, a released query cannot be
+// reused.
+func (q *Queryx) GetRelease(dest interface{}) error {
+	defer q.Release()
+	return q.Get(dest)
+}
+
+// Select scans all rows into a destination, which must be a pointer to slice
+// of any type. If the destination slice type is a struct, then Iter.StructScan
+// will be used on each row. If the destination is some other type, then each
+// row must only have one column which can scan into that type.
+//
+// If no rows were selected, ErrNotFound is NOT returned.
+func (q *Queryx) Select(dest interface{}) error {
+	if q.err != nil {
+		return q.err
+	}
+	return Iter(q.Query).Select(dest)
+}
+
+// SelectRelease calls Select and releases the query, a released query cannot be
+// reused.
+func (q *Queryx) SelectRelease(dest interface{}) error {
+	defer q.Release()
+	return q.Select(dest)
+}