Add drop column if exists

Author: KodaiD

core/src/main/java/com/scalar/db/api/Admin.java

@@ -3,6 +3,7 @@
 import com.scalar.db.common.CoreError;
 import com.scalar.db.exception.storage.ExecutionException;
 import com.scalar.db.io.DataType;
+import com.scalar.db.util.ScalarDbUtils;
 import java.util.Collections;
 import java.util.Map;
 import java.util.Set;
@@ -453,6 +454,31 @@ default void addNewColumnToTable(
   void dropColumnFromTable(String namespace, String table, String columnName)
       throws ExecutionException;
 
+  /**
+   * Drops a column from an existing table. The column cannot be a partition or clustering key.
+   *
+   * @param namespace the table namespace
+   * @param table the table name
+   * @param columnName the name of the column to drop
+   * @param IfExists if set to true, the column will be dropped only if it exists. If set to false,
+   *     it will throw an exception if it does not exist
+   * @throws IllegalArgumentException if the table does not exist
+   * @throws ExecutionException if the operation fails
+   */
+  default void dropColumnFromTable(
+      String namespace, String table, String columnName, boolean IfExists)
+      throws ExecutionException {
+    TableMetadata tableMetadata = getTableMetadata(namespace, table);
+    if (tableMetadata == null) {
+      throw new IllegalArgumentException(
+          CoreError.TABLE_NOT_FOUND.buildMessage(ScalarDbUtils.getFullTableName(namespace, table)));
+    }
+    if (IfExists && !tableMetadata.getColumnNames().contains(columnName)) {
+      return;
+    }
+    dropColumnFromTable(namespace, table, columnName);
+  }
+
   /**
    * Imports an existing table that is not managed by ScalarDB.
    *

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

@@ -201,6 +201,13 @@ public void dropColumnFromTable(String namespace, String table, String columnNam
     distributedTransactionAdmin.dropColumnFromTable(namespace, table, columnName);
   }
 
+  @Override
+  public void dropColumnFromTable(
+      String namespace, String table, String columnName, boolean ifExists)
+      throws ExecutionException {
+    distributedTransactionAdmin.dropColumnFromTable(namespace, table, columnName, ifExists);
+  }
+
   @Override
   public void importTable(String namespace, String table, Map<String, String> options)
       throws ExecutionException {

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

@@ -1099,6 +1099,16 @@ public void dropColumnFromTable_ForPrimaryOrIndexKeyColumn_ShouldThrowIllegalArg
         .isInstanceOf(IllegalArgumentException.class);
   }
 
+  @Test
+  public void dropColumnFromTable_IfExists_ForNonExistingColumn_ShouldNotThrowAnyException() {
+    // Arrange
+
+    // Act Assert
+    assertThatCode(
+            () -> admin.dropColumnFromTable(namespace1, getTable1(), "nonExistingColumn", true))
+        .doesNotThrowAnyException();
+  }
+
   @Test
   public void
       upgrade_WhenMetadataTableExistsButNotNamespacesTable_ShouldCreateNamespacesTableAndImportExistingNamespaces()

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

@@ -858,6 +858,26 @@ public void addNewColumnToTable_AddColumnForEachExistingDataType_ShouldAddNewCol
     }
   }
 
+  @Test
+  public void addNewColumnToTable_ForNonExistingTable_ShouldThrowIllegalArgumentException() {
+    // Arrange
+
+    // Act Assert
+    assertThatThrownBy(
+            () -> admin.addNewColumnToTable(namespace1, TABLE4, COL_NAME2, DataType.TEXT))
+        .isInstanceOf(IllegalArgumentException.class);
+  }
+
+  @Test
+  public void addNewColumnToTable_ForAlreadyExistingColumn_ShouldThrowIllegalArgumentException() {
+    // Arrange
+
+    // Act Assert
+    assertThatThrownBy(
+            () -> admin.addNewColumnToTable(namespace1, TABLE1, COL_NAME2, DataType.TEXT))
+        .isInstanceOf(IllegalArgumentException.class);
+  }
+
   @Test
   public void dropColumnFromTable_DropColumnForEachExistingDataType_ShouldDropColumnsCorrectly()
       throws ExecutionException {
@@ -923,26 +943,6 @@ public void dropColumnFromTable_DropColumnForEachExistingDataType_ShouldDropColu
     }
   }
 
-  @Test
-  public void addNewColumnToTable_ForNonExistingTable_ShouldThrowIllegalArgumentException() {
-    // Arrange
-
-    // Act Assert
-    assertThatThrownBy(
-            () -> admin.addNewColumnToTable(namespace1, TABLE4, COL_NAME2, DataType.TEXT))
-        .isInstanceOf(IllegalArgumentException.class);
-  }
-
-  @Test
-  public void addNewColumnToTable_ForAlreadyExistingColumn_ShouldThrowIllegalArgumentException() {
-    // Arrange
-
-    // Act Assert
-    assertThatThrownBy(
-            () -> admin.addNewColumnToTable(namespace1, TABLE1, COL_NAME2, DataType.TEXT))
-        .isInstanceOf(IllegalArgumentException.class);
-  }
-
   @Test
   public void dropColumnFromTable_ForNonExistingTable_ShouldThrowIllegalArgumentException() {
     // Arrange
@@ -974,6 +974,15 @@ public void dropColumnFromTable_ForPrimaryOrIndexKeyColumn_ShouldThrowIllegalArg
         .isInstanceOf(IllegalArgumentException.class);
   }
 
+  @Test
+  public void dropColumnFromTable_IfNotExists_ForNonExistingColumn_ShouldNotThrowAnyException() {
+    // Arrange
+
+    // Act Assert
+    assertThatCode(() -> admin.dropColumnFromTable(namespace1, TABLE1, "nonExistingColumn", true))
+        .doesNotThrowAnyException();
+  }
+
   @Test
   public void createCoordinatorTables_ShouldCreateCoordinatorTablesCorrectly()
       throws ExecutionException {