data + ci tests for index col and where expressions

Author: alicebob

ci/expr_test.go

@@ -0,0 +1,55 @@
+// +build ci
+
+package ci
+
+import (
+	"testing"
+
+	"github.com/alicebob/sqlittle"
+)
+
+func TestExprCol(t *testing.T) {
+	// index with expression column
+	Compare(
+		t,
+		`
+CREATE TABLE expr (name varchar(255));
+CREATE INDEX expr_name ON expr (substr(name, 0, 10));
+INSERT INTO expr values ("aap"), ("foo"), ("qqq"), ("longestnameever");
+`,
+		`SELECT name FROM expr ORDER BY name`,
+		func(t *testing.T, db *sqlittle.DB) [][]string {
+			var rows [][]string
+			cb := func(r sqlittle.Row) {
+				rows = append(rows, r.ScanStrings())
+			}
+			if err := db.IndexedSelect("expr", "expr_name", cb, "name"); err != nil {
+				t.Fatal(err)
+			}
+			return rows
+		},
+	)
+}
+
+func TestExprWhere(t *testing.T) {
+	// index with WHERE expression
+	Compare(
+		t,
+		`
+CREATE TABLE expr (name varchar(255));
+CREATE INDEX expr_where ON expr (name) WHERE name > "foo";
+INSERT INTO expr values ("aap"), ("foo"), ("qqq"), ("longestnameever");
+`,
+		`SELECT name FROM expr WHERE name > "foo" ORDER BY name`,
+		func(t *testing.T, db *sqlittle.DB) [][]string {
+			var rows [][]string
+			cb := func(r sqlittle.Row) {
+				rows = append(rows, r.ScanStrings())
+			}
+			if err := db.IndexedSelect("expr", "expr_where", cb, "name"); err != nil {
+				t.Fatal(err)
+			}
+			return rows
+		},
+	)
+}

db/schema.go

@@ -40,9 +40,10 @@ type SchemaIndex struct {
 }
 
 type IndexColumn struct {
-	Column    string
-	Collate   string
-	SortOrder sql.SortOrder
+	Column     string
+	Expression string
+	Collate    string
+	SortOrder  sql.SortOrder
 }
 
 func newSchema(table string, master []sqliteMaster) (*Schema, error) {
@@ -200,19 +201,23 @@ func (st *Schema) addCreateIndex(ci sql.CreateIndexStmt) {
 func (st *Schema) toIndexColumns(ci []sql.IndexedColumn) []IndexColumn {
 	var cs []IndexColumn
 	for _, col := range ci {
-		base := st.column(col.Column)
-		if base == nil {
-			base = &TableColumn{} // shouldn't happen
+		c := IndexColumn{
+			Column:     col.Column,
+			Expression: col.Expression,
+			SortOrder:  col.SortOrder,
 		}
-		collate := base.Collate
-		if col.Collate != "" {
-			collate = col.Collate
+		if col.Column != "" {
+			// not an expression column
+			base := st.column(col.Column)
+			if base != nil {
+				collate := base.Collate
+				if col.Collate != "" {
+					collate = col.Collate
+				}
+				c.Collate = collate
+			}
 		}
-		cs = append(cs, IndexColumn{
-			Column:    col.Column,
-			Collate:   collate,
-			SortOrder: col.SortOrder,
-		})
+		cs = append(cs, c)
 	}
 	return cs
 }

indexed_select_test.go

@@ -145,3 +145,65 @@ func TestIndexedSelectDesc(t *testing.T) {
 		t.Errorf("diff:\n%s", diff.LineDiff(spew.Sdump(want), spew.Sdump(have)))
 	}
 }
+
+func TestIndexedSelectExprWhere(t *testing.T) {
+	// index with a WHERE expression
+	db, err := Open("testdata/expr.sqlite")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	var words []string
+	cb := func(r Row) {
+		w, _ := r.ScanString()
+		words = append(words, w)
+	}
+	if err := db.IndexedSelect(
+		"expr",
+		"expr_where",
+		cb,
+		"name",
+	); err != nil {
+		t.Fatal(err)
+	}
+	want := []string{
+		"longestnameever",
+		"qqq",
+	}
+	if have, want := words, want; !reflect.DeepEqual(have, want) {
+		t.Errorf("diff:\n%s", diff.LineDiff(spew.Sdump(want), spew.Sdump(have)))
+	}
+}
+
+func TestIndexedSelectExprCol(t *testing.T) {
+	// index with an expression column
+	db, err := Open("testdata/expr.sqlite")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	var words []string
+	cb := func(r Row) {
+		w, _ := r.ScanString()
+		words = append(words, w)
+	}
+	if err := db.IndexedSelect(
+		"expr",
+		"expr_name",
+		cb,
+		"name",
+	); err != nil {
+		t.Fatal(err)
+	}
+	want := []string{
+		"aap",
+		"foo",
+		"longestnameever", // substr() expression, but we get the value from the row
+		"qqq",
+	}
+	if have, want := words, want; !reflect.DeepEqual(have, want) {
+		t.Errorf("diff:\n%s", diff.LineDiff(spew.Sdump(want), spew.Sdump(have)))
+	}
+}

testdata/Makefile

@@ -3,6 +3,7 @@
 ALL:= \
     alter.sqlite \
     empty.sqlite \
+    expr.sqlite \
     four.sqlite \
     funkykey.sqlite \
     index.sqlite \

testdata/expr.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+set -eu
+TABLE=expr.sqlite
+
+rm -f ${TABLE}
+sqlite3 --batch ${TABLE} <<HERE
+CREATE TABLE expr (name varchar(255));
+CREATE INDEX expr_name ON expr (substr(name, 0, 10));
+CREATE INDEX expr_where ON expr (name) WHERE name > "foo";
+INSERT INTO expr values ("aap"), ("foo"), ("qqq"), ("longestnameever");
+HERE