feat(store): add a helper that marks rows as deleted

internal/store/postgres/postgres.go

@@ -29,6 +29,12 @@ func live(table string) exp.BooleanExpression {
 	return goqu.I(table + ".deleted_at").IsNull()
 }
 
+// softDelete marks rows as deleted instead of removing them. It skips rows
+// that are already deleted, so the first delete time is kept.
+func softDelete(table string) *goqu.UpdateDataset {
+	return dialect.Update(table).Set(goqu.Record{"deleted_at": goqu.L("now()")}).Where(live(table))
+}
+
 // fromLive reads only the rows that are not soft-deleted.
 func fromLive(table string) *goqu.SelectDataset {
 	return dialect.From(table).Where(live(table))

internal/store/postgres/postgres_internal_test.go

@@ -0,0 +1,39 @@
+package postgres
+
+import (
+	"testing"
+
+	"github.com/doug-martin/goqu/v9"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSoftDelete(t *testing.T) {
+	tests := []struct {
+		name       string
+		stmt       *goqu.UpdateDataset
+		wantSQL    string
+		wantParams []any
+	}{
+		{
+			name:       "marks the live rows of the table",
+			stmt:       softDelete(TABLE_DOMAINS),
+			wantSQL:    `UPDATE "domains" SET "deleted_at"=now() WHERE ("domains"."deleted_at" IS NULL)`,
+			wantParams: []any{},
+		},
+		{
+			name:       "joins the caller's filter with AND",
+			stmt:       softDelete(TABLE_DOMAINS).Where(goqu.Ex{"id": "8f2d5b1e-3c4a-4d6b-9e7f-1a2b3c4d5e6f"}),
+			wantSQL:    `UPDATE "domains" SET "deleted_at"=now() WHERE (("domains"."deleted_at" IS NULL) AND ("id" = $1))`,
+			wantParams: []any{"8f2d5b1e-3c4a-4d6b-9e7f-1a2b3c4d5e6f"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gotSQL, gotParams, err := tt.stmt.Prepared(true).ToSQL()
+			assert.NoError(t, err)
+			assert.Equal(t, tt.wantSQL, gotSQL)
+			assert.Equal(t, tt.wantParams, gotParams)
+		})
+	}
+}