From facff58b3b2d069166a997c77e830c69863f1d28 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Carlos=20Nieto?= <jose.carlos@menteslibres.net>
Date: Wed, 7 Oct 2015 07:31:07 -0500
Subject: [PATCH] Adding and using Iterator.Scan() and making the argument to
Iterator.Next() optional.
---
builder.go | 7 ++-
builder/builder.go | 31 ++++++++--
error.go | 3 -
internal/sqladapter/database.go | 2 +-
postgresql/database.go | 103 ++++++++++++++++++++------------
5 files changed, 96 insertions(+), 50 deletions(-)
diff --git a/builder.go b/builder.go
index 7dc52ba9..c04b4719 100644
--- a/builder.go
+++ b/builder.go
@@ -82,9 +82,10 @@ type QueryGetter interface {
}
type Iterator interface {
- All(interface{}) error
- One(interface{}) error
- Next(interface{}) bool
+ All(dest interface{}) error
+ One(dest interface{}) error
+ Scan(dest ...interface{}) error
+ Next(dest ...interface{}) bool
Err() error
Close() error
}
diff --git a/builder/builder.go b/builder/builder.go
index 1a9d026c..7cebb281 100644
--- a/builder/builder.go
+++ b/builder/builder.go
@@ -637,6 +637,13 @@ func NewBuilder(sess sqlDatabase, t *sqlgen.Template) *Builder {
}
}
+func (iter *iterator) Scan(dst ...interface{}) error {
+ if iter.err != nil {
+ return iter.err
+ }
+ return iter.cursor.Scan(dst...)
+}
+
func (iter *iterator) One(dst interface{}) error {
if iter.err != nil {
return iter.err
@@ -670,20 +677,32 @@ func (iter *iterator) Err() (err error) {
return iter.err
}
-func (iter *iterator) Next(dst interface{}) bool {
+func (iter *iterator) Next(dst ...interface{}) bool {
var err error
if iter.err != nil {
return false
}
- if err = sqlutil.FetchRow(iter.cursor, dst); err != nil {
- iter.err = err
- iter.Close()
- return false
+ switch len(dst) {
+ case 0:
+ if ok := iter.cursor.Next(); !ok {
+ iter.err = iter.cursor.Err()
+ iter.Close()
+ return false
+ }
+ return true
+ case 1:
+ if err = sqlutil.FetchRow(iter.cursor, dst[0]); err != nil {
+ iter.err = err
+ iter.Close()
+ return false
+ }
+ return true
}
- return true
+ iter.err = db.ErrUnsupported
+ return false
}
func (iter *iterator) Close() (err error) {
diff --git a/error.go b/error.go
index 01f2b441..3bd51dcf 100644
--- a/error.go
+++ b/error.go
@@ -51,6 +51,3 @@ var (
ErrTooManyClients = errors.New(`Can't connect to database server: too many clients.`)
ErrGivingUpTryingToConnect = errors.New(`Giving up trying to connect: too many clients.`)
)
-
-// Deprecated but kept for backwards compatibility. See: https://github.com/upper/db/issues/18
-var ErrCollectionDoesNotExists = ErrCollectionDoesNotExist
diff --git a/internal/sqladapter/database.go b/internal/sqladapter/database.go
index 5ac62d88..cdf408fb 100644
--- a/internal/sqladapter/database.go
+++ b/internal/sqladapter/database.go
@@ -6,7 +6,6 @@ import (
"time"
"github.com/jmoiron/sqlx"
- _ "github.com/lib/pq" // PostgreSQL driver.
"upper.io/cache"
"upper.io/db"
"upper.io/db/builder"
@@ -141,6 +140,7 @@ func (d *BaseDatabase) C(name string) db.Collection {
if err != nil {
return &adapter.NonExistentCollection{Err: err}
}
+
return c
}
diff --git a/postgresql/database.go b/postgresql/database.go
index 91360c59..9c249779 100644
--- a/postgresql/database.go
+++ b/postgresql/database.go
@@ -38,6 +38,9 @@ type database struct {
var _ = db.Database(&database{})
+// CompileAndReplacePlaceholders compiles the given statement into an string
+// and replaces each generic placeholder with the placeholder the driver
+// expects (if any).
func (d *database) CompileAndReplacePlaceholders(stmt *sqlgen.Statement) (query string) {
buf := stmt.Compile(d.Template())
@@ -54,15 +57,21 @@ func (d *database) CompileAndReplacePlaceholders(stmt *sqlgen.Statement) (query
return query
}
+// Err translates some known errors into generic errors.
func (d *database) Err(err error) error {
- s := err.Error()
- if strings.Contains(s, `too many clients`) || strings.Contains(s, `remaining connection slots are reserved`) {
- return db.ErrTooManyClients
+ if err != nil {
+ s := err.Error()
+ if strings.Contains(s, `too many clients`) || strings.Contains(s, `remaining connection slots are reserved`) {
+ return db.ErrTooManyClients
+ }
+ if strings.Contains(s, `relation`) && strings.Contains(s, `does not exist`) {
+ return db.ErrCollectionDoesNotExist
+ }
}
return err
}
-// Open attempts to connect to the database server using already stored settings.
+// Open attempts to open a connection to the database server.
func (d *database) Open() error {
var sess *sqlx.DB
@@ -78,10 +87,8 @@ func (d *database) Open() error {
return d.Bind(sess)
}
+// Setup configures the adapter.
func (d *database) Setup(connURL db.ConnectionURL) error {
- if d.BaseDatabase != nil {
- d.Close()
- }
d.BaseDatabase = sqladapter.NewDatabase(d, connURL, template.Template)
return d.Open()
}
@@ -93,22 +100,19 @@ func (d *database) Use(name string) (err error) {
return err
}
conn.Database = name
- return d.Setup(conn)
-}
-
-func (d *database) clone() (*database, error) {
- clone := &database{}
- clone.BaseDatabase = d.BaseDatabase.Clone(clone)
- if err := clone.Open(); err != nil {
- return nil, err
+ if d.BaseDatabase != nil {
+ d.Close()
}
- return clone, nil
+ return d.Setup(conn)
}
+// Clone creates a new database connection with the same settings as the
+// original.
func (d *database) Clone() (db.Database, error) {
return d.clone()
}
+// NewTable returns a db.Collection.
func (d *database) NewTable(name string) db.Collection {
return newTable(d, name)
}
@@ -121,13 +125,15 @@ func (d *database) Collections() (collections []string, err error) {
From("information_schema.tables").
Where("table_schema = ?", "public")
- var row struct {
- TableName string `db:"table_name"`
- }
-
iter := q.Iterator()
- for iter.Next(&row) {
- d.Schema().AddTable(row.TableName)
+ defer iter.Close()
+
+ for iter.Next() {
+ var tableName string
+ if err := iter.Scan(&tableName); err != nil {
+ return nil, err
+ }
+ d.Schema().AddTable(tableName)
}
}
@@ -178,18 +184,22 @@ func (d *database) PopulateSchema() (err error) {
d.NewSchema()
- // Get database name.
q := d.Builder().Select(db.Raw{"CURRENT_DATABASE() AS name"})
- var row struct {
- Name string `db:"name"`
- }
+ var dbName string
- if err := q.Iterator().One(&row); err != nil {
- return err
+ iter := q.Iterator()
+ defer iter.Close()
+
+ if iter.Next() {
+ if err := iter.Scan(&dbName); err != nil {
+ return err
+ }
+ } else {
+ return iter.Err()
}
- d.Schema().Name = row.Name
+ d.Schema().Name = dbName
if collections, err = d.Collections(); err != nil {
return err
@@ -204,6 +214,7 @@ func (d *database) PopulateSchema() (err error) {
return err
}
+// TableExists checks whether a table exists and returns an error in case it doesn't.
func (d *database) TableExists(name string) error {
if d.Schema().HasTable(name) {
return nil
@@ -213,15 +224,22 @@ func (d *database) TableExists(name string) error {
From("information_schema.tables").
Where("table_catalog = ? AND table_name = ?", d.Schema().Name, name)
- var row map[string]string
+ iter := q.Iterator()
+ defer iter.Close()
- if err := q.Iterator().One(&row); err != nil {
+ if iter.Next() {
+ var tableName string
+ if err := iter.Scan(&tableName); err != nil {
+ return err
+ }
+ } else {
return db.ErrCollectionDoesNotExist
}
return nil
}
+// TableColumns returns all columns from the given table.
func (d *database) TableColumns(tableName string) ([]string, error) {
s := d.Schema()
@@ -249,6 +267,7 @@ func (d *database) TableColumns(tableName string) ([]string, error) {
return s.Table(tableName).Columns, nil
}
+// TablePrimaryKey returns all primary keys from the given table.
func (d *database) TablePrimaryKey(tableName string) ([]string, error) {
s := d.Schema()
@@ -271,14 +290,24 @@ func (d *database) TablePrimaryKey(tableName string) ([]string, error) {
`).OrderBy("pkey")
iter := q.Iterator()
+ defer iter.Close()
- var row struct {
- Key string `db:"pkey"`
- }
-
- for iter.Next(&row) {
- ts.PrimaryKey = append(ts.PrimaryKey, row.Key)
+ for iter.Next() {
+ var pKey string
+ if err := iter.Scan(&pKey); err != nil {
+ return nil, err
+ }
+ ts.PrimaryKey = append(ts.PrimaryKey, pKey)
}
return ts.PrimaryKey, nil
}
+
+func (d *database) clone() (*database, error) {
+ clone := &database{}
+ clone.BaseDatabase = d.BaseDatabase.Clone(clone)
+ if err := clone.Open(); err != nil {
+ return nil, err
+ }
+ return clone, nil
+}
--
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