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Author: KodaiD

core/src/main/java/com/scalar/db/common/CoreError.java

@@ -799,7 +799,7 @@ public enum CoreError implements ScalarDbError {
   JDBC_UNSUPPORTED_COLUMN_TYPE_CONVERSION(
       Category.USER_ERROR,
       "0239",
-      "The storage does not support column type conversion from %s to %s. Column: %s",
+      "The storage does not support column type conversion from %s to %s",
       "",
       ""),
 

core/src/main/java/com/scalar/db/storage/jdbc/JdbcAdmin.java

@@ -977,15 +977,10 @@ public void alterColumnType(
       String namespace, String table, String columnName, DataType newColumnType)
       throws ExecutionException {
     try {
-      rdbEngine.throwIfAlterColumnTypeNotSupported();
       TableMetadata currentTableMetadata = getTableMetadata(namespace, table);
       assert currentTableMetadata != null;
       DataType currentColumnType = currentTableMetadata.getColumnDataType(columnName);
-      if (!rdbEngine.isTypeConversionSupported(currentColumnType, newColumnType)) {
-        throw new UnsupportedOperationException(
-            CoreError.JDBC_UNSUPPORTED_COLUMN_TYPE_CONVERSION.buildMessage(
-                currentColumnType, newColumnType, columnName));
-      }
+      rdbEngine.throwIfAlterColumnTypeNotSupported(currentColumnType, newColumnType);
 
       TableMetadata updatedTableMetadata =
           TableMetadata.newBuilder(currentTableMetadata)

core/src/main/java/com/scalar/db/storage/jdbc/RdbEngineDb2.java

@@ -549,6 +549,15 @@ public void throwIfRenameColumnNotSupported(String columnName, TableMetadata tab
     }
   }
 
+  @Override
+  public void throwIfAlterColumnTypeNotSupported(DataType from, DataType to) {
+    if (from == DataType.BLOB && to == DataType.TEXT) {
+      throw new UnsupportedOperationException(
+          CoreError.JDBC_UNSUPPORTED_COLUMN_TYPE_CONVERSION.buildMessage(
+              from.toString(), to.toString()));
+    }
+  }
+
   private String getProjection(String columnName, DataType dataType) {
     if (dataType == DataType.DATE) {
       // Selecting a DATE column requires special handling. We need to cast the DATE column values
@@ -574,9 +583,4 @@ public void throwIfCrossPartitionScanOrderingOnBlobColumnNotSupported(
               .buildMessage(orderingOnBlobColumn.get()));
     }
   }
-
-  @Override
-  public boolean isTypeConversionSupported(DataType from, DataType to) {
-    return from != DataType.BLOB || to != DataType.TEXT;
-  }
 }

core/src/main/java/com/scalar/db/storage/jdbc/RdbEngineOracle.java

@@ -444,7 +444,11 @@ public String tryAddIfNotExistsToCreateIndexSql(String createIndexSql) {
   }
 
   @Override
-  public boolean isTypeConversionSupported(DataType from, DataType to) {
-    return from == DataType.INT && to == DataType.BIGINT;
+  public void throwIfAlterColumnTypeNotSupported(DataType from, DataType to) {
+    if (!(from == DataType.INT && to == DataType.BIGINT)) {
+      throw new UnsupportedOperationException(
+          CoreError.JDBC_UNSUPPORTED_COLUMN_TYPE_CONVERSION.buildMessage(
+              from.toString(), to.toString()));
+    }
   }
 }

core/src/main/java/com/scalar/db/storage/jdbc/RdbEngineSqlite.java

@@ -358,13 +358,14 @@ public RdbEngineTimeTypeStrategy<Integer, Long, Long, Long> getTimeTypeStrategy(
   }
 
   @Override
-  public void setConnectionToReadOnly(Connection connection, boolean readOnly) {
-    // Do nothing. SQLite does not support read-only mode.
+  public void throwIfAlterColumnTypeNotSupported(DataType from, DataType to) {
+    throw new UnsupportedOperationException(
+        CoreError.JDBC_SQLITE_ALTER_COLUMN_TYPE_NOT_SUPPORTED.buildMessage(
+            from.toString(), to.toString()));
   }
 
   @Override
-  public void throwIfAlterColumnTypeNotSupported() {
-    throw new UnsupportedOperationException(
-        CoreError.JDBC_SQLITE_ALTER_COLUMN_TYPE_NOT_SUPPORTED.buildMessage());
+  public void setConnectionToReadOnly(Connection connection, boolean readOnly) {
+    // Do nothing. SQLite does not support read-only mode.
   }
 }

core/src/main/java/com/scalar/db/storage/jdbc/RdbEngineStrategy.java

@@ -283,9 +283,11 @@ default void throwIfRenameColumnNotSupported(String columnName, TableMetadata ta
   /**
    * Throws an exception if altering the column type is not supported in the underlying database.
    *
+   * @param from the source data type
+   * @param to the target data type
    * @throws UnsupportedOperationException if altering the column type is not supported
    */
-  default void throwIfAlterColumnTypeNotSupported() {}
+  default void throwIfAlterColumnTypeNotSupported(DataType from, DataType to) {}
 
   default void setConnectionToReadOnly(Connection connection, boolean readOnly)
       throws SQLException {
@@ -303,16 +305,4 @@ default void setConnectionToReadOnly(Connection connection, boolean readOnly)
    */
   default void throwIfCrossPartitionScanOrderingOnBlobColumnNotSupported(
       ScanAll scanAll, TableMetadata metadata) {}
-
-  /**
-   * Returns whether type conversion is supported between the two data types in the underlying
-   * storage.
-   *
-   * @param from the source data type
-   * @param to the target data type
-   * @return true if type conversion is supported, false otherwise
-   */
-  default boolean isTypeConversionSupported(DataType from, DataType to) {
-    return true;
-  }
 }

integration-test/src/main/java/com/scalar/db/api/DistributedTransactionAdminIntegrationTestBase.java

@@ -36,6 +36,9 @@
 
 @TestInstance(TestInstance.Lifecycle.PER_CLASS)
 public abstract class DistributedTransactionAdminIntegrationTestBase {
+  private static final Logger logger =
+      LoggerFactory.getLogger(DistributedTransactionAdminIntegrationTestBase.class);
+
   protected static final String NAMESPACE_BASE_NAME = "int_test_";
   protected static final String TABLE1 = "test_table1";
   protected static final String TABLE2 = "test_table2";
@@ -52,11 +55,11 @@ public abstract class DistributedTransactionAdminIntegrationTestBase {
   protected static final String COL_NAME9 = "c9";
   protected static final String COL_NAME10 = "c10";
   protected static final String COL_NAME11 = "c11";
-  private static final Logger logger =
-      LoggerFactory.getLogger(DistributedTransactionAdminIntegrationTestBase.class);
   private static final String COL_NAME12 = "c12";
   private static final String COL_NAME13 = "c13";
   private static final String COL_NAME14 = "c14";
+  private static final String COL_NAME15 = "c15";
+
   protected static final TableMetadata TABLE_METADATA =
       TableMetadata.newBuilder()
           .addColumn(COL_NAME1, DataType.INT)
@@ -80,7 +83,6 @@ public abstract class DistributedTransactionAdminIntegrationTestBase {
           .addSecondaryIndex(COL_NAME5)
           .addSecondaryIndex(COL_NAME6)
           .build();
-  private static final String COL_NAME15 = "c15";
   protected TransactionFactory transactionFactory;
   protected DistributedTransactionAdmin admin;
   protected String namespace1;