This operation is apparently straightforward: when you drop a column, it should free up the space, and a new column should use more space. Q 12 - By default when a database is dropped in Hive A - the tables are also deleted B - the directory is deleted if there are no tables C - the hdfs blocks are formatted D - Only the comments associated with database is deleted Q 13 - If the database contains some tables then it can be forced to drop without dropping the tables by using the keyword Why did SQL Server take so long to kill the process? The data still lives in a normal file system and nothing is stopping you from changing it without telling Hive about it. When a table is dropped, the database will store the table, along with its dependent objects in the recycle bin so that they can be recovered later. This would contaminate the water supply - … External table files can be accessed and managed by processes outside of Hive. That means that the data, its properties and data layout will and can only be changed via Hive command. Q 12 - By default when a database is dropped in Hive A - the tables are also deleted B - the directory is deleted if there are no tables C - the hdfs blocks are formatted Examples A. If not sure when this happened, leave the Date and time are unknown. When an indexed base table has one of its partitions dropped, this implicitly cascades to drop corresponding partitions from all indexes. Powered by a free Atlassian Confluence Open Source Project License granted to Apache Software Foundation. external table is a way to protect data against accidental drop commands. For example: DROP TABLE Database2.dbo.suppliers; This DROP TABLE example would drop the table called suppliers that is not in the current database in SQL Server . In the Specify when the data was lost step, select the time period when the table was dropped. If a managed table or partition is dropped, the data and metadata associated with that table or partition are deleted. If a tablespace is dropped, what happens to its data files? What Happens When You Drop a Table in a Database? If you do though it violates invariants and expectations of Hive and you might see undefined behavior. There are a few things that happen in Oracle when you drop a table: The data is removed and is no longer accessible. try to use external table in your project ,once you drop it ,do not forget to remove directory if you do not need it anymore . A managed table is stored under the hive.metastore.warehouse.dir path property, by default in a folder path similar to /user/hive/warehouse/databasename.db/tablename/. the difference is , when you drop a table, if it is managed table hive deletes both data and meta data. Another way of deleting data files is to use the INCLUDING clause in the DROP TABLESPACE statement. for example assume you have emp.csv file under directory /data/employee, to create a managed table we use normal syntax like below, create table managedemp(col1 datatype,col2 datatype, ....) row format delimited fields terminated by 'delimiter character', but to create external table ,we use external keyword like below, create external table managedemp(col1 datatype,col2 datatype, ....) row format delimited fields terminated by 'delimiter character'. Dropping a table removes the table definition from the data dictionary. Applies to: SQL Server 2016 (13.x) and later Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics Parallel Data Warehouse You can delete (drop) a table from your database in SQL Server by using SQL Server Management Studio or Transact-SQL. Managed or external tables can be identified using the DESCRIBE FORMATTED table_name command, which will display either MANAGED_TABLE or EXTERNAL_TABLE depending on table type. RESTRICT: Refuse to drop the table if any objects depend on it. DROP TABLE Shippers; Try it Yourself » SQL TRUNCATE TABLE. {"serverDuration": 138, "requestCorrelationId": "96d4108f3f3ee5a8"}, ARCHIVE/UNARCHIVE/TRUNCATE/MERGE/CONCATENATE only work for managed tables, DROP deletes data for managed tables while it only deletes metadata for external ones, ACID/Transactional only works for managed tables, Only the RELY constraint is allowed on external tables, Some Materialized View features only work on managed tables. if it is external table Hive only deletes metadata. What happens if the table that you wish to delete is not in the current database, but rather in another database in SQL Server? ##temp tables (global ones) must be explicitly dropped. SQL Server Drop Table If Exists. I came across a question on ServerFault this afternoon that inflamed my desire to be ultra-geeky (it was really already inflamed after teaching backup and restore internals all afternoon). SQL Server: Who dropped a table, find out from Transaction Log. Drop Table B. There are many features for auditing and check the logging in SQL Server, but you can also directly read the transaction log and can get the necessary details. Regardless of how you drop a managed table, it can take a significant amount of time, depending on the data size. In Hive, ” user/hive/warehouse ” is the default directory. (Table B is renamed as $BIN$B) (Now what will happen to its trigger) 2. the difference is, when you drop a table, if it is managed table hive deletes both data and meta data,if it is external table Hive only deletes metadata. The table is no longer in the data dictionary. drop a table) the data is also changed (in this case the data is deleted). In this post, I am sharing few steps to find out the transactions history for drop commands which executed in SQL Server.