smiklosovic commented on code in PR #4411: URL: https://github.com/apache/cassandra/pull/4411#discussion_r2436317212
########## src/java/org/apache/cassandra/cql3/statements/schema/CommentOnColumnStatement.java: ########## @@ -0,0 +1,146 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.cassandra.cql3.statements.schema; + +import org.apache.cassandra.audit.AuditLogContext; +import org.apache.cassandra.audit.AuditLogEntryType; +import org.apache.cassandra.auth.Permission; +import org.apache.cassandra.cql3.CQLStatement; +import org.apache.cassandra.cql3.ColumnIdentifier; +import org.apache.cassandra.cql3.QualifiedName; +import org.apache.cassandra.cql3.statements.SchemaDescriptionsUtil; +import org.apache.cassandra.schema.ColumnMetadata; +import org.apache.cassandra.schema.KeyspaceMetadata; +import org.apache.cassandra.schema.Keyspaces; +import org.apache.cassandra.schema.Keyspaces.KeyspacesDiff; +import org.apache.cassandra.schema.TableMetadata; +import org.apache.cassandra.service.ClientState; +import org.apache.cassandra.tcm.ClusterMetadata; +import org.apache.cassandra.transport.Event.SchemaChange; +import org.apache.cassandra.transport.Event.SchemaChange.Change; +import org.apache.cassandra.transport.Event.SchemaChange.Target; + +/** + * Handles the execution of COMMENT ON COLUMN CQL statements. + * <p> + * This statement allows users to add descriptive comments to individual columns for documentation purposes. + * Comments are stored in the column metadata and displayed when using DESCRIBE TABLE. + * </p> + * <p> + * Syntax: {@code COMMENT ON COLUMN [keyspace_name.]table_name.column_name IS 'comment text';} + * </p> + * <p> + * Comments can be removed by setting them to an empty string or null. + * </p> + * + * @see CommentOnKeyspaceStatement + * @see CommentOnTableStatement + * @see CommentOnTypeStatement + */ +public final class CommentOnColumnStatement extends AlterSchemaStatement +{ + private final String tableName; + private final ColumnIdentifier columnName; + private final String comment; + + public CommentOnColumnStatement(String keyspaceName, String tableName, ColumnIdentifier columnName, String comment) + { + super(keyspaceName); + this.tableName = tableName; + this.columnName = columnName; + this.comment = comment; + } + + @Override + public void validate(ClientState state) + { + super.validate(state); + SchemaDescriptionsUtil.validateComment(comment); + } + + @Override + public Keyspaces apply(ClusterMetadata metadata) + { + Keyspaces schema = metadata.schema.getKeyspaces(); + KeyspaceMetadata keyspace = schema.getNullable(keyspaceName); + + if (null == keyspace) + throw ire("Keyspace '%s' doesn't exist", keyspaceName); + + TableMetadata table = keyspace.getTableOrViewNullable(tableName); Review Comment: keyspace.getTableNullable() -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
