Improve offset/limit methods

Author: nakamura-to

doma-core/src/main/java/org/seasar/doma/internal/jdbc/dialect/MysqlPagingTransformer.java

@@ -7,7 +7,7 @@
 
 public class MysqlPagingTransformer extends StandardPagingTransformer {
 
-  protected static String MAXIMUM_LIMIT = "18446744073709551615";
+  public static String MAXIMUM_LIMIT = "18446744073709551615";
 
   public MysqlPagingTransformer(long offset, long limit) {
     super(offset, limit);

doma-core/src/main/java/org/seasar/doma/jdbc/criteria/query/CriteriaBuilder.java

@@ -9,6 +9,8 @@ public interface CriteriaBuilder {
 
   void concat(PreparedSqlBuilder buf, Runnable leftOperand, Runnable rightOperand);
 
+  void offsetAndFetch(PreparedSqlBuilder buf, int offset, int limit);
+
   void lockWithTableHint(
       PreparedSqlBuilder buf, ForUpdateOption option, Consumer<PropertyMetamodel<?>> column);
 

doma-core/src/main/java/org/seasar/doma/jdbc/criteria/query/SelectBuilder.java

@@ -21,7 +21,6 @@
 import org.seasar.doma.jdbc.criteria.metamodel.PropertyMetamodel;
 import org.seasar.doma.jdbc.criteria.option.DistinctOption;
 import org.seasar.doma.jdbc.criteria.option.ForUpdateOption;
-import org.seasar.doma.jdbc.dialect.Dialect;
 
 public class SelectBuilder {
   private final Config config;
@@ -30,6 +29,7 @@ public class SelectBuilder {
   private final PreparedSqlBuilder buf;
   private final AliasManager aliasManager;
   private final BuilderSupport support;
+  private final CriteriaBuilder criteriaBuilder;
 
   public SelectBuilder(
       Config config,
@@ -57,6 +57,7 @@ public SelectBuilder(
     this.buf = Objects.requireNonNull(buf);
     this.aliasManager = Objects.requireNonNull(aliasManager);
     support = new BuilderSupport(config, commenter, buf, aliasManager);
+    criteriaBuilder = config.getDialect().getCriteriaBuilder();
   }
 
   public PreparedSql build() {
@@ -72,8 +73,7 @@ void interpret() {
     groupBy();
     having();
     orderBy();
-    limit();
-    offset();
+    offsetAndFetch();
     forUpdate();
   }
 
@@ -101,8 +101,6 @@ private void from() {
     table(context.entityMetamodel);
     if (context.forUpdate != null) {
       ForUpdateOption option = context.forUpdate.option;
-      Dialect dialect = config.getDialect();
-      CriteriaBuilder criteriaBuilder = dialect.getCriteriaBuilder();
       criteriaBuilder.lockWithTableHint(buf, option, this::column);
     }
   }
@@ -199,25 +197,18 @@ public void visit(OrderByItem.Index index) {
     }
   }
 
-  private void limit() {
-    if (context.limit != null) {
-      buf.appendSql(" limit ");
-      buf.appendSql(context.limit.toString());
-    }
-  }
-
-  private void offset() {
-    if (context.offset != null) {
-      buf.appendSql(" offset ");
-      buf.appendSql(context.offset.toString());
+  private void offsetAndFetch() {
+    if (context.offset == null && context.limit == null) {
+      return;
     }
+    int offset = (context.offset == null || context.offset < 0) ? 0 : context.offset;
+    int limit = (context.limit == null || context.limit < 0) ? 0 : context.limit;
+    criteriaBuilder.offsetAndFetch(buf, offset, limit);
   }
 
   private void forUpdate() {
     if (context.forUpdate != null) {
       ForUpdateOption option = context.forUpdate.option;
-      Dialect dialect = config.getDialect();
-      CriteriaBuilder criteriaBuilder = dialect.getCriteriaBuilder();
       criteriaBuilder.forUpdate(buf, option, this::column, aliasManager);
     }
   }

doma-core/src/main/java/org/seasar/doma/jdbc/dialect/MysqlDialect.java

@@ -10,11 +10,13 @@
 import org.seasar.doma.internal.jdbc.dialect.MysqlCountGettingTransformer;
 import org.seasar.doma.internal.jdbc.dialect.MysqlForUpdateTransformer;
 import org.seasar.doma.internal.jdbc.dialect.MysqlPagingTransformer;
+import org.seasar.doma.internal.jdbc.sql.PreparedSqlBuilder;
 import org.seasar.doma.jdbc.JdbcMappingVisitor;
 import org.seasar.doma.jdbc.ScriptBlockContext;
 import org.seasar.doma.jdbc.SelectForUpdateType;
 import org.seasar.doma.jdbc.SqlLogFormattingVisitor;
 import org.seasar.doma.jdbc.SqlNode;
+import org.seasar.doma.jdbc.criteria.query.CriteriaBuilder;
 
 /** A dialect for MySQL. */
 public class MysqlDialect extends StandardDialect {
@@ -130,6 +132,11 @@ public String applyQuote(String name) {
     return OPEN_QUOTE + name + CLOSE_QUOTE;
   }
 
+  @Override
+  public CriteriaBuilder getCriteriaBuilder() {
+    return new MysqlCriteriaBuilder();
+  }
+
   public static class MysqlJdbcMappingVisitor extends StandardJdbcMappingVisitor {}
 
   public static class MysqlSqlLogFormattingVisitor extends StandardSqlLogFormattingVisitor {}
@@ -162,4 +169,18 @@ protected MysqlScriptBlockContext() {
       sqlBlockStartKeywordsList.add(Arrays.asList("begin"));
     }
   }
+
+  public static class MysqlCriteriaBuilder extends StandardCriteriaBuilder {
+    @Override
+    public void offsetAndFetch(PreparedSqlBuilder buf, int offset, int limit) {
+      buf.appendSql(" limit ");
+      if (limit > 0) {
+        buf.appendSql(Integer.toString(limit));
+      } else {
+        buf.appendSql(MysqlPagingTransformer.MAXIMUM_LIMIT);
+      }
+      buf.appendSql(" offset ");
+      buf.appendSql(Integer.toString(offset));
+    }
+  }
 }

doma-core/src/main/java/org/seasar/doma/jdbc/dialect/StandardDialect.java

@@ -1079,6 +1079,18 @@ public void concat(PreparedSqlBuilder buf, Runnable leftOperand, Runnable rightO
       buf.appendSql(")");
     }
 
+    @Override
+    public void offsetAndFetch(PreparedSqlBuilder buf, int offset, int limit) {
+      buf.appendSql(" offset ");
+      buf.appendSql(Integer.toString(offset));
+      buf.appendSql(" rows");
+      if (limit > 0) {
+        buf.appendSql(" fetch first ");
+        buf.appendSql(Integer.toString(limit));
+        buf.appendSql(" rows only");
+      }
+    }
+
     @Override
     public void lockWithTableHint(
         PreparedSqlBuilder buf, ForUpdateOption option, Consumer<PropertyMetamodel<?>> column) {}

doma-core/src/test/java/org/seasar/doma/jdbc/criteria/EntityqlSelectTest.java

@@ -161,7 +161,7 @@ void limit() {
 
     Sql<?> sql = stmt.asSql();
     assertEquals(
-        "select t0_.ID, t0_.NAME, t0_.SALARY, t0_.VERSION from EMP t0_ limit 5",
+        "select t0_.ID, t0_.NAME, t0_.SALARY, t0_.VERSION from EMP t0_ offset 0 rows fetch first 5 rows only",
         sql.getFormattedSql());
   }
 
@@ -182,7 +182,7 @@ void offset() {
 
     Sql<?> sql = stmt.asSql();
     assertEquals(
-        "select t0_.ID, t0_.NAME, t0_.SALARY, t0_.VERSION from EMP t0_ offset 5",
+        "select t0_.ID, t0_.NAME, t0_.SALARY, t0_.VERSION from EMP t0_ offset 5 rows",
         sql.getFormattedSql());
   }
 

doma-core/src/test/java/org/seasar/doma/jdbc/criteria/NativeSqlSelectTest.java

@@ -655,7 +655,8 @@ void limit() {
     Buildable<?> stmt = nativeSql.from(e).limit(10).select(e.id);
 
     Sql<?> sql = stmt.asSql();
-    assertEquals("select t0_.ID from EMP t0_ limit 10", sql.getFormattedSql());
+    assertEquals(
+        "select t0_.ID from EMP t0_ offset 0 rows fetch first 10 rows only", sql.getFormattedSql());
   }
 
   @Test
@@ -673,7 +674,7 @@ void offset() {
     Buildable<?> stmt = nativeSql.from(e).offset(10).select(e.id);
 
     Sql<?> sql = stmt.asSql();
-    assertEquals("select t0_.ID from EMP t0_ offset 10", sql.getFormattedSql());
+    assertEquals("select t0_.ID from EMP t0_ offset 10 rows", sql.getFormattedSql());
   }
 
   @Test