A table is the data storage unit in MaxCompute. A table is a two-dimensional data structure composed of rows and columns. Each row represents a record, and each column represents a field with the same data type. One record can contain one or more columns. The column name and data type comprise the schema of a table.
- Data of internal tables is stored in MaxCompute. The columns in external tables can be of any data types supported by MaxCompute.
- Data of external tables is not stored in MaxCompute. Instead, this data can be stored in OSS or OTS. MaxCompute only records metadata of the external tables. You can use MaxCompute to process unstructured data of external tables, such as video, audio, or meteorological data.
- Unlike databases such as Oracle, MaxCompute does not automatically create DUAL tables.
- If you are using DUAL tables for testing, you can run the
CREATE TABLE IF NOT EXISTS DUAL (DUMMY VARCHAR(1));command to create a table named DUAL with only one field for testing.
- DUAL tables are used in the same way as Oracle. For example, you can run the
select getdate() from dual;to use a DUAL table.