sql: match postgres FOREIGN KEY constraint name

Release note (sql change): Newly created FOREIGN KEYs now have the same
constraint name as postgres - `<table>_<cols>_fkey`. Previously, this
was `fk_<cols>_ref_<target>`.

pkg/sql/catalog/tabledesc/index.go

@@ -11,6 +11,9 @@
 package tabledesc
 
 import (
+	"fmt"
+	"strings"
+
 	"github.com/cockroachdb/cockroach/pkg/geo/geoindex"
 	"github.com/cockroachdb/cockroach/pkg/sql/catalog"
 	"github.com/cockroachdb/cockroach/pkg/sql/catalog/descpb"
@@ -523,3 +526,8 @@ func lazyAllocAppendIndex(slice *[]catalog.Index, idx catalog.Index, cap int) {
 	}
 	*slice = append(*slice, idx)
 }
+
+// ForeignKeyConstraintName forms a default foreign key constraint name.
+func ForeignKeyConstraintName(fromTable string, columnNames []string) string {
+	return fmt.Sprintf("%s_%s_fkey", fromTable, strings.Join(columnNames, "_"))
+}

pkg/sql/create_table.go

@@ -960,7 +960,7 @@ func ResolveFK(
 	constraintName := string(d.Name)
 	if constraintName == "" {
 		constraintName = tabledesc.GenerateUniqueName(
-			fmt.Sprintf("fk_%s_ref_%s", string(d.FromCols[0]), target.Name),
+			tabledesc.ForeignKeyConstraintName(tbl.GetName(), d.FromCols.ToStrings()),
 			func(p string) bool {
 				_, ok := constraintInfo[p]
 				return ok

pkg/sql/opt/testutils/testcat/BUILD.bazel

@@ -26,6 +26,7 @@ go_library(
         "//pkg/settings/cluster",
         "//pkg/sql/catalog/colinfo",
         "//pkg/sql/catalog/descpb",
+        "//pkg/sql/catalog/tabledesc",
         "//pkg/sql/catalog/typedesc",
         "//pkg/sql/enum",
         "//pkg/sql/oidext",

pkg/sql/opt/testutils/testcat/create_table.go

@@ -23,6 +23,7 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/settings/cluster"
 	"github.com/cockroachdb/cockroach/pkg/sql/catalog/colinfo"
 	"github.com/cockroachdb/cockroach/pkg/sql/catalog/descpb"
+	"github.com/cockroachdb/cockroach/pkg/sql/catalog/tabledesc"
 	"github.com/cockroachdb/cockroach/pkg/sql/opt/cat"
 	"github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
 	"github.com/cockroachdb/cockroach/pkg/sql/sessiondatapb"
@@ -422,8 +423,9 @@ func (tc *Catalog) resolveFK(tab *Table, d *tree.ForeignKeyConstraintTableDef) {
 
 	constraintName := string(d.Name)
 	if constraintName == "" {
-		constraintName = fmt.Sprintf(
-			"fk_%s_ref_%s", string(d.FromCols[0]), targetTable.TabName.Table(),
+		constraintName = tabledesc.ForeignKeyConstraintName(
+			tab.TabName.Table(),
+			d.FromCols.ToStrings(),
 		)
 	}