What are the advantages and disadvantages of row database and column database? Compare the execution efficiency of row database and column database.

The traditional row database is stored by rows, so it is very expensive to maintain a large number of indexes and materialized views in time (processing) and space (storage). On the contrary, the data in a column database is stored by columns, and each column is stored separately, so the data is an index. Only the columns involved in the query are accessed, which greatly reduces the system I/O, and each column processes one row. Moreover, because the data types are consistent and the data characteristics are similar, it is very convenient to compress. Row database is good at random reading operation, and column database is better at large-scale data query.