diff --git a/.php-cs-fixer.dist.php b/.php-cs-fixer.dist.php
index 841e41e5b..7571f3048 100644
--- a/.php-cs-fixer.dist.php
+++ b/.php-cs-fixer.dist.php
@@ -13,12 +13,16 @@
 ]);
 
 return (new Config())
+    ->setRiskyAllowed(true)
     ->setParallelConfig(ParallelConfigFactory::detect())
     ->setRules([
         '@PER-CS3.0' => true,
         'no_unused_imports' => true,
         'ordered_class_elements' => true,
         'class_attributes_separation' => ['elements' => ['method' => 'one']],
+        'declare_strict_types' => true,
+        'native_function_invocation' => true,
+        'native_constant_invocation' => true,
         'fully_qualified_strict_types' => [
             'import_symbols' => true
         ],
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7e623c632..d1941284e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,7 +4,8 @@
 
 - Bug #1127: Fix `AbstractSchema::hasTable()` and `AbstractSchema::hasView()` methods to support names quoted with curly
   brackets `{{%table}}` (@batyrmastyr)
-- Enh #1145: Explicitly import classes, functions, and constants in "use" section (@mspirkov)
+- Enh #1145, #1148: Explicitly import classes, functions, and constants in "use" section (@mspirkov)
+- Enh #1148: Add `declare(strict_types=1)` to `Yiisoft\Db\Constant\ColumnInfoSource` (@mspirkov)
 
 ## 2.0.0 December 05, 2025
 
diff --git a/src/Constant/ColumnInfoSource.php b/src/Constant/ColumnInfoSource.php
index 79cb4f448..b88fecb03 100644
--- a/src/Constant/ColumnInfoSource.php
+++ b/src/Constant/ColumnInfoSource.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Yiisoft\Db\Constant;
 
 use Yiisoft\Db\Schema\Column\ColumnFactoryInterface;
diff --git a/src/Debug/CommandInterfaceProxy.php b/src/Debug/CommandInterfaceProxy.php
index 1e18f1078..9619cc645 100644
--- a/src/Debug/CommandInterfaceProxy.php
+++ b/src/Debug/CommandInterfaceProxy.php
@@ -12,6 +12,9 @@
 use Yiisoft\Db\Query\QueryInterface;
 use Yiisoft\Db\Schema\Column\ColumnInterface;
 
+use function count;
+use function func_get_args;
+
 final class CommandInterfaceProxy implements CommandInterface
 {
     public function __construct(
diff --git a/src/Debug/DatabaseCollector.php b/src/Debug/DatabaseCollector.php
index 76bb89e2a..6fb91f91b 100644
--- a/src/Debug/DatabaseCollector.php
+++ b/src/Debug/DatabaseCollector.php
@@ -8,6 +8,8 @@
 use Yiisoft\Yii\Debug\Collector\CollectorTrait;
 use Yiisoft\Yii\Debug\Collector\SummaryCollectorInterface;
 
+use function count;
+
 final class DatabaseCollector implements SummaryCollectorInterface
 {
     use CollectorTrait;
diff --git a/src/Debug/TransactionInterfaceDecorator.php b/src/Debug/TransactionInterfaceDecorator.php
index d2b6a667f..0906da414 100644
--- a/src/Debug/TransactionInterfaceDecorator.php
+++ b/src/Debug/TransactionInterfaceDecorator.php
@@ -6,6 +6,8 @@
 
 use Yiisoft\Db\Transaction\TransactionInterface;
 
+use function func_get_args;
+
 final class TransactionInterfaceDecorator implements TransactionInterface
 {
     public function __construct(
diff --git a/src/Exception/ConvertException.php b/src/Exception/ConvertException.php
index 3b46a7953..e64271c25 100644
--- a/src/Exception/ConvertException.php
+++ b/src/Exception/ConvertException.php
@@ -6,6 +6,8 @@
 
 use PDOException;
 
+use const PHP_EOL;
+
 /**
  * Converts an exception into a more specific one.
  *
diff --git a/src/Exception/Exception.php b/src/Exception/Exception.php
index 0b9231da0..be0318a89 100644
--- a/src/Exception/Exception.php
+++ b/src/Exception/Exception.php
@@ -6,6 +6,8 @@
 
 use Stringable;
 
+use const PHP_EOL;
+
 /**
  * Represents an exception that's caused by some DB-related operations.
  *
diff --git a/src/Helper/DbArrayHelper.php b/src/Helper/DbArrayHelper.php
index c6fef23eb..438090aba 100644
--- a/src/Helper/DbArrayHelper.php
+++ b/src/Helper/DbArrayHelper.php
@@ -23,6 +23,10 @@
 use function iterator_to_array;
 use function range;
 
+use const PREG_SPLIT_NO_EMPTY;
+use const SORT_ASC;
+use const SORT_NUMERIC;
+
 /**
  * Array manipulation methods.
  *
diff --git a/src/Helper/DbUuidHelper.php b/src/Helper/DbUuidHelper.php
index 5958997a0..c157e9877 100644
--- a/src/Helper/DbUuidHelper.php
+++ b/src/Helper/DbUuidHelper.php
@@ -10,6 +10,7 @@
 use function hex2bin;
 use function preg_match;
 use function str_replace;
+use function strlen;
 
 final class DbUuidHelper
 {
diff --git a/src/Query/Query.php b/src/Query/Query.php
index 7b183f9b8..f499893f5 100644
--- a/src/Query/Query.php
+++ b/src/Query/Query.php
@@ -44,6 +44,11 @@
 use function substr;
 use function trim;
 
+use const PHP_INT_MAX;
+use const PREG_SPLIT_NO_EMPTY;
+use const SORT_ASC;
+use const SORT_DESC;
+
 /**
  * Represents a `SELECT` SQL statement in a way that's independent of DBMS.
  *
diff --git a/src/QueryBuilder/AbstractDDLQueryBuilder.php b/src/QueryBuilder/AbstractDDLQueryBuilder.php
index e0f598a28..b6d2e3c88 100644
--- a/src/QueryBuilder/AbstractDDLQueryBuilder.php
+++ b/src/QueryBuilder/AbstractDDLQueryBuilder.php
@@ -16,6 +16,8 @@
 use function is_string;
 use function preg_split;
 
+use const PREG_SPLIT_NO_EMPTY;
+
 /**
  * It's used to create and change the structure of database objects in a database.
  *
diff --git a/src/QueryBuilder/AbstractDQLQueryBuilder.php b/src/QueryBuilder/AbstractDQLQueryBuilder.php
index 6892e6543..3eae9b427 100644
--- a/src/QueryBuilder/AbstractDQLQueryBuilder.php
+++ b/src/QueryBuilder/AbstractDQLQueryBuilder.php
@@ -59,6 +59,9 @@
 use function strtoupper;
 use function trim;
 
+use const PREG_SPLIT_NO_EMPTY;
+use const SORT_DESC;
+
 /**
  * It's used to query data from a database.
  *
diff --git a/src/QueryBuilder/Condition/Simple.php b/src/QueryBuilder/Condition/Simple.php
index 0828828a3..78db26ced 100644
--- a/src/QueryBuilder/Condition/Simple.php
+++ b/src/QueryBuilder/Condition/Simple.php
@@ -8,6 +8,7 @@
 use Yiisoft\Db\Expression\ExpressionInterface;
 
 use function array_key_exists;
+use function is_string;
 
 /**
  * Represents a simple condition like `"column" operator value`.
diff --git a/src/Schema/Column/BitColumn.php b/src/Schema/Column/BitColumn.php
index 9e8a304fd..0d28b3c8b 100644
--- a/src/Schema/Column/BitColumn.php
+++ b/src/Schema/Column/BitColumn.php
@@ -7,6 +7,8 @@
 use Yiisoft\Db\Constant\ColumnType;
 use Yiisoft\Db\Expression\ExpressionInterface;
 
+use function is_int;
+
 /**
  * Represents the metadata for a bit column.
  */
diff --git a/src/Schema/Column/ColumnBuilder.php b/src/Schema/Column/ColumnBuilder.php
index b0ec0622a..f661a78c1 100644
--- a/src/Schema/Column/ColumnBuilder.php
+++ b/src/Schema/Column/ColumnBuilder.php
@@ -6,6 +6,8 @@
 
 use Yiisoft\Db\Constant\ColumnType;
 
+use const PHP_INT_SIZE;
+
 /**
  * Column builder for database {@see ColumnInterface} instances.
  *
diff --git a/tests/Common/CommonColumnFactoryTest.php b/tests/Common/CommonColumnFactoryTest.php
index 9ad1bdcd9..5ce5330cf 100644
--- a/tests/Common/CommonColumnFactoryTest.php
+++ b/tests/Common/CommonColumnFactoryTest.php
@@ -16,6 +16,8 @@
 use Yiisoft\Db\Tests\Provider\ColumnFactoryProvider;
 use Yiisoft\Db\Tests\Support\IntegrationTestCase;
 
+use function is_scalar;
+
 abstract class CommonColumnFactoryTest extends IntegrationTestCase
 {
     public function testConstructColumnClassMap(): void
diff --git a/tests/Common/CommonCommandTest.php b/tests/Common/CommonCommandTest.php
index dae3156df..456bf64f4 100644
--- a/tests/Common/CommonCommandTest.php
+++ b/tests/Common/CommonCommandTest.php
@@ -39,6 +39,10 @@
 use function is_string;
 use function setlocale;
 use function str_starts_with;
+use function count;
+use function is_resource;
+
+use const LC_NUMERIC;
 
 abstract class CommonCommandTest extends IntegrationTestCase
 {
diff --git a/tests/Common/CommonQueryBuilderTest.php b/tests/Common/CommonQueryBuilderTest.php
index 90e1b79bd..7de27c91d 100644
--- a/tests/Common/CommonQueryBuilderTest.php
+++ b/tests/Common/CommonQueryBuilderTest.php
@@ -43,8 +43,11 @@
 use function PHPUnit\Framework\assertEmpty;
 use function PHPUnit\Framework\assertSame;
 use function sort;
+use function in_array;
 
 use const SORT_NATURAL;
+use const SORT_ASC;
+use const SORT_DESC;
 
 abstract class CommonQueryBuilderTest extends IntegrationTestCase
 {
diff --git a/tests/Common/CommonQueryTest.php b/tests/Common/CommonQueryTest.php
index 4d6a76157..f878802bc 100644
--- a/tests/Common/CommonQueryTest.php
+++ b/tests/Common/CommonQueryTest.php
@@ -18,6 +18,9 @@
 
 use function array_keys;
 
+use const SORT_ASC;
+use const SORT_DESC;
+
 abstract class CommonQueryTest extends IntegrationTestCase
 {
     public function testAddGroupByExpression(): void
diff --git a/tests/Db/Driver/Pdo/PdoDriverTest.php b/tests/Db/Driver/Pdo/PdoDriverTest.php
index f8898b563..36f793c2f 100644
--- a/tests/Db/Driver/Pdo/PdoDriverTest.php
+++ b/tests/Db/Driver/Pdo/PdoDriverTest.php
@@ -11,6 +11,8 @@
 use SensitiveParameterValue;
 use TypeError;
 
+use const PHP_VERSION_ID;
+
 /**
  * @group db
  *
diff --git a/tests/Db/Exception/ConvertExceptionTest.php b/tests/Db/Exception/ConvertExceptionTest.php
index a7424389d..bb742331a 100644
--- a/tests/Db/Exception/ConvertExceptionTest.php
+++ b/tests/Db/Exception/ConvertExceptionTest.php
@@ -8,6 +8,8 @@
 use PHPUnit\Framework\TestCase;
 use Yiisoft\Db\Exception\ConvertException;
 
+use const PHP_EOL;
+
 /**
  * @group db
  *
diff --git a/tests/Db/Helper/DbArrayHelperTest.php b/tests/Db/Helper/DbArrayHelperTest.php
index f3d87cc08..1164f8e12 100644
--- a/tests/Db/Helper/DbArrayHelperTest.php
+++ b/tests/Db/Helper/DbArrayHelperTest.php
@@ -11,6 +11,8 @@
 use Yiisoft\Db\Tests\Provider\DbArrayHelperProvider;
 use Exception;
 
+use const E_WARNING;
+
 /**
  * @group db
  */
diff --git a/tests/Db/Query/QueryTest.php b/tests/Db/Query/QueryTest.php
index e6da7fdf8..c5ef88e83 100644
--- a/tests/Db/Query/QueryTest.php
+++ b/tests/Db/Query/QueryTest.php
@@ -14,6 +14,8 @@
 
 use function PHPUnit\Framework\assertSame;
 
+use const SORT_DESC;
+
 /**
  * @group db
  */
diff --git a/tests/Db/QueryBuilder/QueryBuilderTest.php b/tests/Db/QueryBuilder/QueryBuilderTest.php
index 546b6de76..e13b97d20 100644
--- a/tests/Db/QueryBuilder/QueryBuilderTest.php
+++ b/tests/Db/QueryBuilder/QueryBuilderTest.php
@@ -26,6 +26,8 @@
 use function fopen;
 use function stream_context_create;
 
+use const SORT_DESC;
+
 /**
  * @group db
  */
diff --git a/tests/Provider/QueryBuilderProvider.php b/tests/Provider/QueryBuilderProvider.php
index 3c98ebb37..3e0912fb5 100644
--- a/tests/Provider/QueryBuilderProvider.php
+++ b/tests/Provider/QueryBuilderProvider.php
@@ -52,6 +52,8 @@
 
 use function fopen;
 
+use const PREG_SET_ORDER;
+
 class QueryBuilderProvider
 {
     protected static string $likeEscapeCharSql = '';
diff --git a/tests/Provider/SchemaProvider.php b/tests/Provider/SchemaProvider.php
index 68dffacd0..b3c8b1853 100644
--- a/tests/Provider/SchemaProvider.php
+++ b/tests/Provider/SchemaProvider.php
@@ -12,6 +12,8 @@
 use Yiisoft\Db\Constraint\Index;
 use Yiisoft\Db\Schema\SchemaInterface;
 
+use function sprintf;
+
 class SchemaProvider
 {
     public static function columns(): array
diff --git a/tests/Support/AnyCaseValue.php b/tests/Support/AnyCaseValue.php
index 585580849..851f1942b 100644
--- a/tests/Support/AnyCaseValue.php
+++ b/tests/Support/AnyCaseValue.php
@@ -5,6 +5,7 @@
 namespace Yiisoft\Db\Tests\Support;
 
 use function strtolower;
+use function is_array;
 
 final class AnyCaseValue extends CompareValue
 {
diff --git a/tests/Support/Assert.php b/tests/Support/Assert.php
index 909d1da46..4aa5d3301 100644
--- a/tests/Support/Assert.php
+++ b/tests/Support/Assert.php
@@ -22,6 +22,9 @@
 use function ksort;
 use function ltrim;
 use function strtolower;
+use function count;
+
+use const SORT_STRING;
 
 /**
  * @psalm-suppress PropertyNotSetInConstructor
diff --git a/tests/Support/TraversableObject.php b/tests/Support/TraversableObject.php
index a20455f05..40290efb1 100644
--- a/tests/Support/TraversableObject.php
+++ b/tests/Support/TraversableObject.php
@@ -8,6 +8,8 @@
 use Exception;
 use Iterator;
 
+use function array_key_exists;
+
 /**
  * TraversableObject
  *