Fix invalid delete statement (#539)

Author: nakamura-to

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

@@ -58,11 +58,22 @@ public void table(EntityMetamodel<?> entityMetamodel) {
         entityType.getQualifiedTableName(
             config.getNaming()::apply, config.getDialect()::applyQuote));
     buf.appendSql(" ");
+    String alias = getAlias(entityMetamodel);
+    buf.appendSql(alias);
+  }
+
+  public void alias(EntityMetamodel<?> entityMetamodel) {
+    String alias = getAlias(entityMetamodel);
+    buf.appendSql(alias);
+  }
+
+  public String getAlias(EntityMetamodel<?> entityMetamodel) {
+    EntityType<?> entityType = entityMetamodel.asType();
     String alias = aliasManager.getAlias(entityMetamodel);
     if (alias == null) {
       throw new DomaException(Message.DOMA6003, entityType.getName());
     }
-    buf.appendSql(alias);
+    return alias;
   }
 
   public void operand(Operand operand) {

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

@@ -12,6 +12,7 @@
 import org.seasar.doma.jdbc.criteria.metamodel.EntityMetamodel;
 
 public class DeleteBuilder {
+  private final Config config;
   private final DeleteContext context;
   private final Function<String, String> commenter;
   private final PreparedSqlBuilder buf;
@@ -37,6 +38,7 @@ public DeleteBuilder(
       PreparedSqlBuilder buf,
       AliasManager aliasManager) {
     Objects.requireNonNull(config);
+    this.config = Objects.requireNonNull(config);
     this.context = Objects.requireNonNull(context);
     this.commenter = Objects.requireNonNull(commenter);
     this.buf = Objects.requireNonNull(buf);
@@ -45,7 +47,12 @@ public DeleteBuilder(
   }
 
   public PreparedSql build() {
-    buf.appendSql("delete from ");
+    buf.appendSql("delete");
+    if (config.getDialect().supportsAliasInDeleteClause()) {
+      buf.appendSql(" ");
+      alias(context.entityMetamodel);
+    }
+    buf.appendSql(" from ");
     table(context.entityMetamodel);
     if (!context.where.isEmpty()) {
       buf.appendSql(" where ");
@@ -59,6 +66,10 @@ public PreparedSql build() {
     return buf.build(commenter);
   }
 
+  private void alias(EntityMetamodel<?> entityMetamodel) {
+    support.alias(entityMetamodel);
+  }
+
   private void table(EntityMetamodel<?> entityMetamodel) {
     support.table(entityMetamodel);
   }

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

@@ -123,6 +123,19 @@ public interface Dialect {
    */
   boolean supportsIdentityReservation();
 
+  /**
+   * Whether this object supports alias reference in DELETE clause as follows:
+   *
+   * <pre>
+   * DELETE t FROM employee t
+   * </pre>
+   *
+   * @return {@code true}, if this object supports it
+   */
+  default boolean supportsAliasInDeleteClause() {
+    return false;
+  }
+
   /**
    * Returns an SQL object to get IDENTITY values that are generated in the database.
    *

doma-core/src/main/java/org/seasar/doma/jdbc/dialect/Mssql2008Dialect.java

@@ -114,6 +114,11 @@ public boolean supportsAutoGeneratedKeys() {
     return true;
   }
 
+  @Override
+  public boolean supportsAliasInDeleteClause() {
+    return true;
+  }
+
   @Override
   public String getScriptBlockDelimiter() {
     return "GO";

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

@@ -91,6 +91,11 @@ public boolean supportsSelectForUpdate(SelectForUpdateType type, boolean withTar
     return type == SelectForUpdateType.NORMAL && !withTargets;
   }
 
+  @Override
+  public boolean supportsAliasInDeleteClause() {
+    return true;
+  }
+
   @Override
   protected SqlNode toCountCalculatingSqlNode(SqlNode sqlNode) {
     MysqlCountCalculatingTransformer transformer = new MysqlCountCalculatingTransformer();

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

@@ -8,6 +8,7 @@
 import org.seasar.doma.jdbc.criteria.entity.Dept_;
 import org.seasar.doma.jdbc.criteria.entity.Emp_;
 import org.seasar.doma.jdbc.criteria.statement.Statement;
+import org.seasar.doma.jdbc.dialect.MysqlDialect;
 
 class NativeSqlDeleteTest {
 
@@ -22,6 +23,19 @@ void deleteFrom() {
     assertEquals("delete from EMP t0_", sql.getFormattedSql());
   }
 
+  @Test
+  void aliasInDeleteClause() {
+    MockConfig config = new MockConfig();
+    config.dialect = new MysqlDialect();
+    NativeSql nativeSql = new NativeSql(config);
+
+    Emp_ e = new Emp_();
+    Statement<Integer> stmt = nativeSql.delete(e);
+
+    Sql<?> sql = stmt.asSql();
+    assertEquals("delete t0_ from EMP t0_", sql.getFormattedSql());
+  }
+
   @Test
   void where() {
     Emp_ e = new Emp_();