fix: quote string default values in generated SQL

packages/jao/lib/src/db/adapters/sqlite.dart

@@ -7,6 +7,7 @@ library;
 import 'dart:async';
 import 'dart:io';
 import 'package:sqlite3/sqlite3.dart' as sqlite;
+import '../../migrations/operations.dart' show sqlDefault;
 import '../../migrations/schema.dart' show ForeignKeyDefinition, OnDeleteAction;
 import '../connection.dart';
 
@@ -703,7 +704,7 @@ List<String> generateTableRecreationSql({
         buffer.write(' NOT NULL');
       }
       if (defaultValue != null) {
-        buffer.write(' DEFAULT $defaultValue');
+        buffer.write(' DEFAULT ${sqlDefault(defaultValue)}');
       }
     }
 

packages/jao/lib/src/fields/field_def.dart

@@ -311,8 +311,6 @@ class EnumField<T extends Enum> extends Field {
   });
 }
 
-// === Primary Key ===
-
 /// Auto-incrementing primary key
 @immutable
 class AutoField extends Field {
@@ -331,8 +329,6 @@ class UuidPrimaryKey extends UuidField {
   const UuidPrimaryKey({super.column}) : super(autoGenerate: true, nullable: false, unique: true);
 }
 
-// === Relationships ===
-
 /// Foreign key relationship
 @immutable
 class ForeignKey extends Field {

packages/jao/lib/src/fields/field_ref.dart

@@ -24,8 +24,6 @@ abstract class FieldRef<T> {
   /// Get the column reference expression
   ColumnRef get col => ColumnRef(name, table: table ?? '');
 
-  // === Common lookups available on all fields ===
-
   /// Exact match: field = value
   Q eq(T value) => Q(Comparison(col, ComparisonOp.eq, Value(value)));
 
@@ -41,16 +39,12 @@ abstract class FieldRef<T> {
   /// In list: field IN (values)
   Q inList(List<T> values) => Q(Comparison(col, ComparisonOp.inList, Value(values)));
 
-  // === Ordering ===
-
   /// Order ascending
   OrderBy asc() => OrderBy(col, ascending: true);
 
   /// Order descending
   OrderBy desc() => OrderBy(col, ascending: false);
 
-  // === F-expression comparison ===
-
   /// Compare with another field
   Q eqField(FieldRef<T> other) => Q(Comparison(col, ComparisonOp.eq, other.col));
 
@@ -125,8 +119,6 @@ abstract class NumericFieldRef<T extends num> extends ComparableFieldRef<T> {
       };
 }
 
-// === Concrete Field Reference Types ===
-
 /// String field reference with text-specific lookups
 @immutable
 class StringFieldRef extends FieldRef<String> {
@@ -205,8 +197,6 @@ class DurationFieldRef extends ComparableFieldRef<Duration> {
   const DurationFieldRef(super.name, {super.table});
 }
 
-// === Related Field References (for ForeignKey, etc.) ===
-
 /// Reference to a related model for traversing relationships
 @immutable
 class RelatedFieldRef<T> extends FieldRef<T> {

packages/jao/lib/src/migrations/operations.dart

@@ -7,6 +7,19 @@ import 'package:meta/meta.dart';
 import '../db/connection.dart';
 import 'schema.dart';
 
+/// Quote a default value for SQL if needed.
+/// Numbers, booleans, and SQL keywords (CURRENT_TIMESTAMP) are emitted as-is.
+/// Everything else is wrapped in single quotes.
+String sqlDefault(String value) {
+  if (num.tryParse(value) != null) return value;
+  final lower = value.toLowerCase();
+  if (lower == 'true' || lower == 'false') return value;
+  if (lower == 'current_timestamp' || lower == 'null') return value;
+  if (value.startsWith("'") && value.endsWith("'")) return value;
+  final escaped = value.replaceAll("'", "''");
+  return "'$escaped'";
+}
+
 /// Base class for all migration operations.
 @immutable
 abstract class MigrationOperation {
@@ -22,8 +35,6 @@ abstract class MigrationOperation {
   bool get isReversible;
 }
 
-// === Table Operations ===
-
 /// Create a new table.
 @immutable
 class CreateTable extends MigrationOperation {
@@ -92,8 +103,8 @@ class CreateTable extends MigrationOperation {
     }
 
     // Default value
-    if (col.defaultValue != null) {
-      buffer.write(' DEFAULT ${col.defaultValue}');
+    if (col.defaultValue case final defaultValue?) {
+      buffer.write(' DEFAULT ${sqlDefault(defaultValue)}');
     }
 
     // Check constraint
@@ -191,8 +202,6 @@ class RenameTable extends MigrationOperation {
   bool get isReversible => true;
 }
 
-// === Column Operations ===
-
 /// Add a column to an existing table.
 @immutable
 class AddColumn extends MigrationOperation {
@@ -219,8 +228,8 @@ class AddColumn extends MigrationOperation {
       buffer.write(' NOT NULL');
     }
 
-    if (column.defaultValue != null) {
-      buffer.write(' DEFAULT ${column.defaultValue}');
+    if (column.defaultValue case final defaultValue?) {
+      buffer.write(' DEFAULT ${sqlDefault(defaultValue)}');
     }
 
     return buffer.toString();
@@ -308,8 +317,8 @@ class AlterColumn extends MigrationOperation {
     }
 
     // Change default
-    if (modification.defaultValue != null) {
-      statements.add('ALTER TABLE $table ALTER COLUMN $column SET DEFAULT ${modification.defaultValue}');
+    if (modification.defaultValue case final defaultValue?) {
+      statements.add('ALTER TABLE $table ALTER COLUMN $column SET DEFAULT ${sqlDefault(defaultValue)}');
     } else if (modification.dropDefault) {
       statements.add('ALTER TABLE $table ALTER COLUMN $column DROP DEFAULT');
     }
@@ -329,8 +338,6 @@ class AlterColumn extends MigrationOperation {
   bool get isReversible => false;
 }
 
-// === Index Operations ===
-
 /// Create an index.
 @immutable
 class CreateIndex extends MigrationOperation {
@@ -385,8 +392,6 @@ class DropIndex extends MigrationOperation {
   bool get isReversible => false;
 }
 
-// === Constraint Operations ===
-
 /// Add a foreign key constraint.
 @immutable
 class AddForeignKey extends MigrationOperation {
@@ -442,8 +447,6 @@ class DropConstraint extends MigrationOperation {
   bool get isReversible => false;
 }
 
-// === Raw SQL Operations ===
-
 /// Execute raw SQL.
 @immutable
 class RawSql extends MigrationOperation {

packages/jao/lib/src/query/aggregates.dart

@@ -95,8 +95,6 @@ class Least extends FunctionCall {
   Least(List<Expression> exprs) : super('LEAST', exprs);
 }
 
-// === String Functions ===
-
 /// String length
 @immutable
 class Length extends FunctionCall {
@@ -140,8 +138,6 @@ class Replace extends FunctionCall {
   Replace(Expression expr, String from, String to) : super('REPLACE', [expr, Value(from), Value(to)]);
 }
 
-// === Date/Time Functions ===
-
 /// Current date
 @immutable
 class CurrentDate extends FunctionCall {
@@ -173,8 +169,6 @@ class DateTrunc extends FunctionCall {
   DateTrunc(String precision, Expression expr) : super('DATE_TRUNC', [Value(precision), expr]);
 }
 
-// === Math Functions ===
-
 /// Absolute value
 @immutable
 class Abs extends FunctionCall {