25.6.16.22 The ndbinfo dictionary_columns Table (original) (raw)

25.6.16.22 The ndbinfo dictionary_columns Table

The table provides NDB dictionary information about columns of NDB tables.dictionary_columns has the columns listed here (with brief descriptions):

• table_id
  ID of the table containing the column
• column_id
  The column's unique ID
• name
  Name of the column
• column_type
  Data type of the column from the NDB API; seeColumn::Type, for possible values
• default_value
  The column's default value, if any
• nullable
  Either of NULL or NOT NULL
• array_type
  The column's internal attribute storage format; one ofFIXED, SHORT_VAR, orMEDIUM_VAR; for more information, seeColumn::ArrayType, in the NDB API documentation
• storage_type
  Type of storage used by the table; either ofMEMORY or DISK
• primary_key
1 if this is a primary key column, otherwise 0
• partition_key
1 if this is a partitioning key column, otherwise 0
• dynamic
1 if the column is dynamic, otherwise0
• auto_inc
1 if this is anAUTO_INCREMENT column, otherwise0

You can obtain information about all of the columns in a given table by joining dictionary_columns with thedictionary_tables table, like this:

SELECT dc.*
  FROM dictionary_columns dc
JOIN dictionary_tables dt
  ON dc.table_id=dt.table_id
WHERE dt.table_name='t1'
  AND dt.database_name='mydb';

The dictionary_columns table was added in NDB 8.0.29.

Note

Blob columns are not shown in this table. This is a known issue.