From cdabf24277853af632725a9f7d0f8bcb28e52928 Mon Sep 17 00:00:00 2001
From: Vladimir Mihailenco <vladimir.webdev@gmail.com>
Date: Sun, 29 Apr 2018 15:08:49 +0300
Subject: [PATCH] More docs

---
 db.go        |  2 ++
 error.go     |  5 +++++
 orm/query.go | 10 ++++++++--
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/db.go b/db.go
index c443d946..4ef11f93 100644
--- a/db.go
+++ b/db.go
@@ -47,6 +47,7 @@ func (db *DB) Options() *Options {
 	return db.opt
 }
 
+// Context returns DB context.
 func (db *DB) Context() context.Context {
 	if db.ctx != nil {
 		return db.ctx
@@ -54,6 +55,7 @@ func (db *DB) Context() context.Context {
 	return context.Background()
 }
 
+// WithContext copies the DB, sets context and returns copied DB.
 func (db *DB) WithContext(ctx context.Context) *DB {
 	return &DB{
 		opt:   db.opt,
diff --git a/error.go b/error.go
index b906ea2a..99520760 100644
--- a/error.go
+++ b/error.go
@@ -7,7 +7,12 @@ import (
 	"github.com/go-pg/pg/internal"
 )
 
+// ErrNoRows is returned by QueryOne and ExecOne when query returned zero rows
+// but at least one row is expected.
 var ErrNoRows = internal.ErrNoRows
+
+// ErrMultiRows is returned by QueryOne and ExecOne when query returned
+// multiple rows but exactly one row is expected.
 var ErrMultiRows = internal.ErrMultiRows
 
 // Error represents an error returned by PostgreSQL server
diff --git a/orm/query.go b/orm/query.go
index 8a68b28a..d15b2d5d 100644
--- a/orm/query.go
+++ b/orm/query.go
@@ -158,8 +158,14 @@ func (q *Query) TableExpr(expr string, params ...interface{}) *Query {
 	return q
 }
 
-// Column adds column to the Query quoting it according to PostgreSQL rules.
-// ColumnExpr can be used to bypass quoting restriction.
+// Column adds a column to the Query quoting it according to PostgreSQL rules.
+// ColumnExpr can be used to bypass quoting restriction. Column name can be:
+//   - column_name,
+//   - table_alias.column_name,
+//   - table_alias.*,
+//   - RelationName,
+//   - RelationName.column_name,
+//   - RelationName._ to join relation without selecting relation data.
 func (q *Query) Column(columns ...string) *Query {
 	for _, column := range columns {
 		if column == "_" {