Get Column Metadata

Column metadata details of a single column of a table in the Catalyst Data Store can be retrieved either by using the columnID or the column name.

The table_service reference used in the below code snippets can either be a table instance or table meta.

Get a Column’s Metadata by ID

You can fetch a column’s meta data of a particular table using get_column_details() method.

    

        
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         #Get column's metadata using columnID
datastore_service = app.datastore()
table_service = datastore_service.table("CITY")
column_data = table_service.get_column_details(5249000000032372)

    

A sample response is shown below :

    

        
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         {
  table_id: "5249000000011745",
  column_sequence: "5",
  column_name: "CITYNAME",
  category: 2,
  data_type: "varchar",
  max_length: "100",
  is_mandatory: false,
  decimal_digits: "2",
  is_unique: true,
  search_index_enabled: false,
  column_id: "5249000000032372"
}

    

Get a Column’s Metadata by Name

An alternative way to get the meta data of a column is, referring to the column_name. This returns the same response as that of the previous one.

The column meta will not involve any further operations. Therefore the response is returned here directly.

    

        
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         #Get column's metadata using column name
datastore_service = app.datastore()
table_service = datastore_service.table("CITY")
column_data = table_service.get_column_details("CITYNAME")

    

A sample response is shown below :

    

        
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         {
  table_id: "5249000000011745",
  column_sequence: "5",
  column_name: "CITYNAME",
  category: 2,
  data_type: "varchar",
  max_length: "100",
  is_mandatory: false,
  decimal_digits: "2",
  is_unique: true,
  search_index_enabled: false,
  column_id: "2305000000007725"
}
    

Get Metadata of All Columns

In addition to getting the meta data of a single column, you can retrieve the meta data of all the columns in a particular table using get_all_columns() method.

    

        
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         #Get metadata of all columns
datastore_service = app.datastore()
table_service = datastore_service.table("CITY")
columns = table_service.get_all_columns()

    

A sample response is shown below :

    

        
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         [
  {
    table_id: "5249000000011745",
    column_sequence: "1",
    column_name: "ROWID",
    category: 1,
    data_type: "bigint",
    max_length: "50",
    is_mandatory: false,
    decimal_digits: "2",
    is_unique: false,
    search_index_enabled: false,
    column_id: "2136000000007784"
  },
  {
    table_id: "5249000000011745",
    column_sequence: "2",
    column_name: "CREATORID",
    category: 1,
    data_type: "bigint",
    max_length: "50",
    is_mandatory: false,
    decimal_digits: "2",
    is_unique: false,
    search_index_enabled: true,
    column_id: "2136000000007785"
  },
  {
    table_id: "5249000000011745",
    column_sequence: "3",
    column_name: "CREATEDTIME",
    category: 1,
    data_type: "datetime",
    max_length: "50",
    is_mandatory: false,
    decimal_digits: "2",
    is_unique: false,
    search_index_enabled: true,
    column_id: "2136000000007786"
  },
  {
    table_id: "5249000000011745",
    column_sequence: "4",
    column_name: "MODIFIEDTIME",
    category: 1,
    data_type: "datetime",
    max_length: "50",
    is_mandatory: false,
    decimal_digits: "2",
    is_unique: false,
    search_index_enabled: true,
    column_id: "2136000000007787"
  },
  {
    table_id: "5249000000011745",
    column_sequence: "5",
    column_name: "CITYNAME",
    category: 2,
    data_type: "varchar",
    max_length: "100",
    is_mandatory: false,
    decimal_digits: "2",
    is_unique: true,
    search_index_enabled: true,
    column_id: "2136000000008588"
  }
]