diff --git a/api/src/main/java/cc/carm/lib/easysql/api/action/PreparedSQLUpdateAction.java b/api/src/main/java/cc/carm/lib/easysql/api/action/PreparedSQLUpdateAction.java
index f4c1dad..39e6beb 100644
--- a/api/src/main/java/cc/carm/lib/easysql/api/action/PreparedSQLUpdateAction.java
+++ b/api/src/main/java/cc/carm/lib/easysql/api/action/PreparedSQLUpdateAction.java
@@ -17,6 +17,7 @@ public interface PreparedSQLUpdateAction<T extends Number> extends SQLUpdateActi
      *
      * @param params 参数内容
      * @return {@link PreparedSQLUpdateAction}
+     * @since 0.4.0
      */
     PreparedSQLUpdateAction<T> setParams(@Nullable Iterable<Object> params);
 
diff --git a/api/src/main/java/cc/carm/lib/easysql/api/action/PreparedSQLUpdateBatchAction.java b/api/src/main/java/cc/carm/lib/easysql/api/action/PreparedSQLUpdateBatchAction.java
index 9bc961a..d5d965d 100644
--- a/api/src/main/java/cc/carm/lib/easysql/api/action/PreparedSQLUpdateBatchAction.java
+++ b/api/src/main/java/cc/carm/lib/easysql/api/action/PreparedSQLUpdateBatchAction.java
@@ -35,6 +35,7 @@ public interface PreparedSQLUpdateBatchAction<T extends Number> extends SQLActio
      * @param keyTypeClass 自增序列的数字类型
      * @param <N>          自增键序列类型 {@link Number}
      * @return {@link SQLUpdateAction}
+     * @since 0.4.0
      */
     <N extends Number> PreparedSQLUpdateBatchAction<N> returnGeneratedKeys(Class<N> keyTypeClass);
 
diff --git a/api/src/main/java/cc/carm/lib/easysql/api/action/SQLUpdateAction.java b/api/src/main/java/cc/carm/lib/easysql/api/action/SQLUpdateAction.java
index d7b0253..12f75a6 100644
--- a/api/src/main/java/cc/carm/lib/easysql/api/action/SQLUpdateAction.java
+++ b/api/src/main/java/cc/carm/lib/easysql/api/action/SQLUpdateAction.java
@@ -18,6 +18,7 @@ public interface SQLUpdateAction<T extends Number> extends SQLAction<T> {
      * @param keyTypeClass 自增序列的数字类型
      * @param <N>          自增键序列类型 {@link Number}
      * @return {@link SQLUpdateAction}
+     * @since 0.4.0
      */
     <N extends Number> SQLUpdateAction<N> returnGeneratedKey(Class<N> keyTypeClass);
 
diff --git a/api/src/main/java/cc/carm/lib/easysql/api/function/SQLFunction.java b/api/src/main/java/cc/carm/lib/easysql/api/function/SQLFunction.java
index cf803fe..8f1b776 100644
--- a/api/src/main/java/cc/carm/lib/easysql/api/function/SQLFunction.java
+++ b/api/src/main/java/cc/carm/lib/easysql/api/function/SQLFunction.java
@@ -4,6 +4,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.sql.SQLException;
+import java.util.Objects;
 
 @FunctionalInterface
 public interface SQLFunction<T, R> {
@@ -11,4 +12,23 @@ public interface SQLFunction<T, R> {
     @Nullable
     R apply(@NotNull T t) throws SQLException;
 
+    default <V> SQLFunction<V, R> compose(@NotNull SQLFunction<? super V, ? extends T> before) {
+        Objects.requireNonNull(before);
+        return (V v) -> {
+            T t = before.apply(v);
+            if (t == null) return null;
+            else return apply(t);
+        };
+    }
+
+    default <V> SQLFunction<T, V> then(@NotNull SQLFunction<? super R, ? extends V> after) {
+        Objects.requireNonNull(after);
+        return (T t) -> {
+            R r = apply(t);
+            if (r == null) return null;
+            else return after.apply(r);
+        };
+    }
+
+
 }
diff --git a/demo/src/test/java/cc/carm/lib/easysql/EasySQLTest.java b/demo/src/test/java/cc/carm/lib/easysql/EasySQLTest.java
index 69d410f..a8762f1 100644
--- a/demo/src/test/java/cc/carm/lib/easysql/EasySQLTest.java
+++ b/demo/src/test/java/cc/carm/lib/easysql/EasySQLTest.java
@@ -6,23 +6,38 @@ import cc.carm.lib.easysql.tests.*;
 import com.zaxxer.hikari.HikariConfig;
 import com.zaxxer.hikari.HikariDataSource;
 import org.jetbrains.annotations.NotNull;
+import org.junit.After;
+import org.junit.Before;
 import org.junit.Test;
 
-import java.math.BigInteger;
 import java.util.LinkedHashSet;
 import java.util.Set;
 
 public class EasySQLTest {
 
+    protected SQLManager sqlManager;
 
-    @Test
-    public void onTest() {
+    @Before
+    public void initDatabase() {
         HikariConfig config = new HikariConfig();
         config.setDriverClassName("org.h2.Driver");
         config.setJdbcUrl("jdbc:h2:mem:test;DB_CLOSE_DELAY=-1;MODE=MYSQL;");
 
-        SQLManager sqlManager = new SQLManagerImpl(new HikariDataSource(config), "test");
-        sqlManager.setDebugMode(true);
+        this.sqlManager = new SQLManagerImpl(new HikariDataSource(config), "test");
+        this.sqlManager.setDebugMode(true);
+    }
+
+    @After
+    public void shutdownDatabase() {
+        if (sqlManager.getDataSource() instanceof HikariDataSource) {
+            //Close bee connection pool
+            ((HikariDataSource) sqlManager.getDataSource()).close();
+        }
+    }
+
+
+    @Test
+    public void onTest() {
 
         print("加载测试类...");
         Set<TestHandler> tests = new LinkedHashSet<>();
@@ -62,10 +77,6 @@ public class EasySQLTest {
                 success, (tests.size() - success)
         );
 
-        if (sqlManager.getDataSource() instanceof HikariDataSource) {
-            //Close bee connection pool
-            ((HikariDataSource) sqlManager.getDataSource()).close();
-        }
 
     }