Added support for add column and drop column

ice/src/main/java/com/altinity/ice/cli/Main.java

@@ -10,12 +10,14 @@
 package com.altinity.ice.cli;
 
 import ch.qos.logback.classic.Level;
+import com.altinity.ice.cli.internal.cmd.AddColumn;
 import com.altinity.ice.cli.internal.cmd.Check;
 import com.altinity.ice.cli.internal.cmd.CreateNamespace;
 import com.altinity.ice.cli.internal.cmd.CreateTable;
 import com.altinity.ice.cli.internal.cmd.DeleteNamespace;
 import com.altinity.ice.cli.internal.cmd.DeleteTable;
 import com.altinity.ice.cli.internal.cmd.Describe;
+import com.altinity.ice.cli.internal.cmd.DropColumn;
 import com.altinity.ice.cli.internal.cmd.Insert;
 import com.altinity.ice.cli.internal.cmd.Scan;
 import com.altinity.ice.cli.internal.config.Config;
@@ -426,6 +428,41 @@ void deleteNamespace(
     }
   }
 
+  @CommandLine.Command(name = "add-column", description = "Add a column to an existing table.")
+  void addColumn(
+      @CommandLine.Parameters(
+              arity = "1",
+              paramLabel = "<name>",
+              description = "Table name (e.g. ns1.table1)")
+          String name,
+      @CommandLine.Parameters(
+              arity = "1",
+              paramLabel = "<column>",
+              description = "Column definition: name:type[:comment] (e.g. 'age:int:User age')")
+          String column)
+      throws IOException {
+    try (RESTCatalog catalog = loadCatalog(this.configFile())) {
+      TableIdentifier tableId = TableIdentifier.parse(name);
+      AddColumn.run(catalog, tableId, column);
+    }
+  }
+
+  @CommandLine.Command(name = "drop-column", description = "Drop a column from an existing table.")
+  void dropColumn(
+      @CommandLine.Parameters(
+              arity = "1",
+              paramLabel = "<name>",
+              description = "Table name (e.g. ns1.table1)")
+          String name,
+      @CommandLine.Parameters(arity = "1", paramLabel = "<column>", description = "Column name")
+          String column)
+      throws IOException {
+    try (RESTCatalog catalog = loadCatalog(this.configFile())) {
+      TableIdentifier tableId = TableIdentifier.parse(name);
+      DropColumn.run(catalog, tableId, column);
+    }
+  }
+
   private RESTCatalog loadCatalog() throws IOException {
     return loadCatalog(this.configFile());
   }

ice/src/main/java/com/altinity/ice/cli/internal/cmd/AddColumn.java

@@ -0,0 +1,121 @@
+/*
+ * Copyright (c) 2025 Altinity Inc and/or its affiliates. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ */
+package com.altinity.ice.cli.internal.cmd;
+
+import java.io.IOException;
+import org.apache.iceberg.Table;
+import org.apache.iceberg.Transaction;
+import org.apache.iceberg.UpdateSchema;
+import org.apache.iceberg.catalog.Catalog;
+import org.apache.iceberg.catalog.TableIdentifier;
+import org.apache.iceberg.types.Types;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class AddColumn {
+  private static final Logger logger = LoggerFactory.getLogger(AddColumn.class);
+
+  private AddColumn() {}
+
+  public static void run(Catalog catalog, TableIdentifier tableId, String columnDefinition)
+      throws IOException {
+
+    Table table = catalog.loadTable(tableId);
+
+    // Parse column definition
+    ColumnSpec columnSpec = parseColumnDefinition(columnDefinition);
+
+    // Apply schema change
+    Transaction transaction = table.newTransaction();
+    UpdateSchema updateSchema = transaction.updateSchema();
+
+    updateSchema.addColumn(columnSpec.name, columnSpec.type, columnSpec.comment);
+
+    updateSchema.commit();
+    transaction.commitTransaction();
+
+    logger.info("Successfully added column '{}' to table: {}", columnSpec.name, tableId);
+  }
+
+  private static ColumnSpec parseColumnDefinition(String columnDefinition) {
+    String[] parts = columnDefinition.split(":");
+    if (parts.length < 2) {
+      throw new IllegalArgumentException(
+          "Invalid column definition format. Expected: name:type[:comment] (e.g. 'age:int:User age')");
+    }
+
+    String columnName = parts[0];
+    String columnType = parts[1];
+    String comment = parts.length > 2 ? parts[2] : null;
+
+    Types.NestedField field = parseColumnType(columnName, columnType, comment);
+
+    return new ColumnSpec(columnName, field.type(), comment);
+  }
+
+  private static Types.NestedField parseColumnType(String name, String type, String comment) {
+    Types.NestedField field;
+
+    switch (type.toLowerCase()) {
+      case "string":
+      case "varchar":
+        field = Types.NestedField.optional(-1, name, Types.StringType.get(), comment);
+        break;
+      case "int":
+      case "integer":
+        field = Types.NestedField.optional(-1, name, Types.IntegerType.get(), comment);
+        break;
+      case "long":
+      case "bigint":
+        field = Types.NestedField.optional(-1, name, Types.LongType.get(), comment);
+        break;
+      case "double":
+        field = Types.NestedField.optional(-1, name, Types.DoubleType.get(), comment);
+        break;
+      case "float":
+        field = Types.NestedField.optional(-1, name, Types.FloatType.get(), comment);
+        break;
+      case "boolean":
+        field = Types.NestedField.optional(-1, name, Types.BooleanType.get(), comment);
+        break;
+      case "date":
+        field = Types.NestedField.optional(-1, name, Types.DateType.get(), comment);
+        break;
+      case "timestamp":
+        field = Types.NestedField.optional(-1, name, Types.TimestampType.withoutZone(), comment);
+        break;
+      case "timestamptz":
+        field = Types.NestedField.optional(-1, name, Types.TimestampType.withZone(), comment);
+        break;
+      case "binary":
+        field = Types.NestedField.optional(-1, name, Types.BinaryType.get(), comment);
+        break;
+      default:
+        throw new IllegalArgumentException(
+            "Unsupported column type: "
+                + type
+                + ". Supported types: string, int, long, double, float, boolean, date, timestamp, timestamptz, binary");
+    }
+
+    return field;
+  }
+
+  private static class ColumnSpec {
+    final String name;
+    final org.apache.iceberg.types.Type type;
+    final String comment;
+
+    ColumnSpec(String name, org.apache.iceberg.types.Type type, String comment) {
+      this.name = name;
+      this.type = type;
+      this.comment = comment;
+    }
+  }
+}

ice/src/main/java/com/altinity/ice/cli/internal/cmd/DropColumn.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2025 Altinity Inc and/or its affiliates. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ */
+package com.altinity.ice.cli.internal.cmd;
+
+import java.io.IOException;
+import org.apache.iceberg.Table;
+import org.apache.iceberg.Transaction;
+import org.apache.iceberg.UpdateSchema;
+import org.apache.iceberg.catalog.Catalog;
+import org.apache.iceberg.catalog.TableIdentifier;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class DropColumn {
+  private static final Logger logger = LoggerFactory.getLogger(DropColumn.class);
+
+  private DropColumn() {}
+
+  public static void run(Catalog catalog, TableIdentifier tableId, String columnName)
+      throws IOException {
+
+    Table table = catalog.loadTable(tableId);
+
+    // Validate that the column exists
+    if (table.schema().findField(columnName) == null) {
+      throw new IllegalArgumentException(
+          "Column '" + columnName + "' does not exist in table: " + tableId);
+    }
+
+    // Apply schema change
+    Transaction transaction = table.newTransaction();
+    UpdateSchema updateSchema = transaction.updateSchema();
+
+    updateSchema.deleteColumn(columnName);
+
+    updateSchema.commit();
+    transaction.commitTransaction();
+
+    logger.info("Successfully dropped column '{}' from table: {}", columnName, tableId);
+  }
+}