Extend Table join interface.

sqlbuilder/column.go

@@ -4,6 +4,7 @@ package sqlbuilder
 
 import (
 	"bytes"
+	"github.com/dropbox/godropbox/database/sqltypes"
 	"regexp"
 
 	"github.com/dropbox/godropbox/errors"
@@ -14,6 +15,7 @@ import (
 // Representation of a table for query generation
 type Column interface {
 	isProjectionInterface
+	isExpressionInterface
 
 	Name() string
 	// Serialization for use in column lists
@@ -24,6 +26,14 @@ type Column interface {
 	// Internal function for tracking table that a column belongs to
 	// for the purpose of serialization
 	setTableName(table string) error
+
+	Eq(rhs Expression) BoolExpression
+
+	Gte(rhs Expression) BoolExpression
+	GteLiteral(rhs interface{}) BoolExpression
+
+	Lte(rhs Expression) BoolExpression
+	LteLiteral(rhs interface{}) BoolExpression
 }
 
 type NullableColumn bool
@@ -37,7 +47,6 @@ const (
 type NonAliasColumn interface {
 	Column
 	isOrderByClauseInterface
-	isExpressionInterface
 }
 
 type Collation string
@@ -94,6 +103,26 @@ func (c *baseColumn) SerializeSql(out *bytes.Buffer) error {
 	return nil
 }
 
+func (c *baseColumn) Eq(rhs Expression) BoolExpression {
+	return Eq(c, rhs)
+}
+
+func (c *baseColumn) Gte(rhs Expression) BoolExpression {
+	return Gte(c, rhs)
+}
+
+func (c *baseColumn) GteLiteral(rhs interface{}) BoolExpression {
+	return Gte(c, Literal(rhs))
+}
+
+func (c *baseColumn) Lte(rhs Expression) BoolExpression {
+	return Lte(c, rhs)
+}
+
+func (c *baseColumn) LteLiteral(literal interface{}) BoolExpression {
+	return Lte(c, Literal(literal))
+}
+
 type bytesColumn struct {
 	baseColumn
 	isExpression
@@ -305,3 +334,27 @@ func (c *deferredLookupColumn) setTableName(table string) error {
 		"Lookup column '%s' should never have setTableName called on it",
 		c.colName)
 }
+
+func (c *deferredLookupColumn) Eq(rhs Expression) BoolExpression {
+	lit, ok := rhs.(*literalExpression)
+	if ok && sqltypes.Value(lit.value).IsNull() {
+		return newBoolExpression(c, rhs, []byte(" IS "))
+	}
+	return newBoolExpression(c, rhs, []byte(" = "))
+}
+
+func (c *deferredLookupColumn) Gte(rhs Expression) BoolExpression {
+	return Gte(c, rhs)
+}
+
+func (c *deferredLookupColumn) GteLiteral(rhs interface{}) BoolExpression {
+	return Gte(c, Literal(rhs))
+}
+
+func (c *deferredLookupColumn) Lte(rhs Expression) BoolExpression {
+	return Lte(c, rhs)
+}
+
+func (c *deferredLookupColumn) LteLiteral(literal interface{}) BoolExpression {
+	return Lte(c, Literal(literal))
+}

sqlbuilder/table.go

@@ -26,6 +26,8 @@ type ReadableTable interface {
 	// Creates a inner join table expression using onCondition.
 	InnerJoinOn(table ReadableTable, onCondition BoolExpression) ReadableTable
 
+	InnerJoinUsing(table ReadableTable, col1 Column, col2 Column) ReadableTable
+
 	// Creates a left join table expression using onCondition.
 	LeftJoinOn(table ReadableTable, onCondition BoolExpression) ReadableTable
 
@@ -170,6 +172,14 @@ func (t *Table) InnerJoinOn(
 	return InnerJoinOn(t, table, onCondition)
 }
 
+func (t *Table) InnerJoinUsing(
+	table ReadableTable,
+	col1 Column,
+	col2 Column) ReadableTable {
+
+	return InnerJoinOn(t, table, col1.Eq(col2))
+}
+
 // Creates a left join table expression using onCondition.
 func (t *Table) LeftJoinOn(
 	table ReadableTable,
@@ -308,6 +318,14 @@ func (t *joinTable) InnerJoinOn(
 	return InnerJoinOn(t, table, onCondition)
 }
 
+func (t *joinTable) InnerJoinUsing(
+	table ReadableTable,
+	col1 Column,
+	col2 Column) ReadableTable {
+
+	return InnerJoinOn(t, table, col1.Eq(col2))
+}
+
 func (t *joinTable) LeftJoinOn(
 	table ReadableTable,
 	onCondition BoolExpression) ReadableTable {

tests/generator_test.go

@@ -134,11 +134,11 @@ func TestSelect_ScanToSlice(t *testing.T) {
 func TestJoinQueryStruct(t *testing.T) {
 
 	query := FilmActor.
-		InnerJoinOn(Actor, sqlbuilder.Eq(FilmActor.ActorID, Actor.ActorID)).
-		InnerJoinOn(Film, sqlbuilder.Eq(FilmActor.FilmID, Film.FilmID)).
-		InnerJoinOn(Language, sqlbuilder.Eq(Film.LanguageID, Language.LanguageID)).
+		InnerJoinUsing(Actor, FilmActor.ActorID, Actor.ActorID).
+		InnerJoinUsing(Film, FilmActor.FilmID, Film.FilmID).
+		InnerJoinUsing(Language, Film.LanguageID, Language.LanguageID).
 		Select(FilmActor.AllColumns, Film.AllColumns, Language.AllColumns, Actor.AllColumns).
-		Where(sqlbuilder.And(sqlbuilder.Gte(FilmActor.ActorID, sqlbuilder.Literal(1)), sqlbuilder.Lte(FilmActor.ActorID, sqlbuilder.Literal(2))))
+		Where(sqlbuilder.And(FilmActor.ActorID.GteLiteral(1), FilmActor.ActorID.LteLiteral(2)))
 
 	queryStr, err := query.String()
 	assert.NilError(t, err)
@@ -165,7 +165,7 @@ func TestJoinQuerySlice(t *testing.T) {
 	filmsPerLanguage := []FilmsPerLanguage{}
 	limit := 15
 
-	query := Film.InnerJoinOn(Language, sqlbuilder.Eq(Film.LanguageID, Language.LanguageID)).
+	query := Film.InnerJoinUsing(Language, Film.LanguageID, Language.LanguageID).
 		Select(Language.AllColumns, Film.AllColumns).
 		Limit(15)
 
@@ -205,7 +205,7 @@ func TestJoinQuerySliceWithPtrs(t *testing.T) {
 
 	limit := int64(3)
 
-	query := Film.InnerJoinOn(Language, sqlbuilder.Eq(Film.LanguageID, Language.LanguageID)).
+	query := Film.InnerJoinUsing(Language, Film.LanguageID, Language.LanguageID).
 		Select(Language.AllColumns, Film.AllColumns).
 		Limit(limit)