Databases with many director tables#

Tip

See the following document first:

Types of tables in Qserv (CONCEPTS)

The API supports ingesting multiple director tables within a single catalog. Each director table can optionally have its own set of dependent tables. This section demonstrates the necessary configuration for the following table set:

director	dependent
dir_1	dep_1_1
	dep_1_2
	dep_1_3
dir_2	dep_2_1
dir_2	dep_2_2
dir_3

In this example, there are 3 director tables. Each (except the third one dir_3) has its own set of dependent tables. The key attributes that govern dependencies between the tables are specified in the section Registering tables (REST). The document mentions the following required attributes that need to be provided in the JSON specification of each table:

attribute

value

comment

is_partitioned

1

Same value for both director and dependent tables.

director_table

string

Where:

director tables should have the empty string here.
dependent tables should have the name of the corresponding director table here.

director_key

string

The non-empty string specifying the name of the corresponding column must be provided here. Depending on the type of the table, this name corresponds to either:

The primary key in the director table, or
The foreign key pointing to the corresponding director’s primary key in the dependent tables.

The director tables are required to have the following attributes:

attribute	value	comment
`latitude_key` `longitude_key`	string	The names of the director table’s columns that were used for partitioning the table data into chunks.

The dependent tables may also include the attributes latitude_key and longitude_key if their input data was partitioned using the columns specified by these attributes. If not, these attributes can be omitted from the table’s JSON specification.

The following table illustrates how JSON configurations for all the above-mentioned tables might look like (the examples were simplified for clarity):

director

dependents

{ "table" : "dir_1",
  "is_partitioned" : 1,
  "director_table" : "",
  "director_key" : "objectId",
  "latitude_key" : "ra",
  "longitude_key" : "dec"
}

{ "table" : "dep_1_1",
  "is_partitioned" : 1,
  "director_table" : "dir_1",
  "director_key" : "dep_objectId"
}

Note: Attributes latitude_key and longitude_key were not provided. This is allowed for the dependent tables.

{ "table" : "dep_1_2",
  "is_partitioned" : 1,
  "director_table" : "dir_1",
  "director_key" : "dep_objectId"
  "latitude_key" : "",
  "longitude_key" : ""
}

Note: Attributes latitude_key and longitude_key were provided. However the values were empty strings, which is allowed for the dependent tables.

{ "table" : "dep_1_3",
  "is_partitioned" : 1,
  "director_table" : "dir_1",
  "director_key" : "dep_objectId"
  "latitude_key" : "dep_ra",
  "longitude_key" : "dep_dec"
}

{ "table" : "dir_2",
  "is_partitioned" : 1,
  "director_table" : "",
  "director_key" : "id",
  "latitude_key" : "coord_ra",
  "longitude_key" : "coord_dec"
}

{ "table" : "dep_2_1",
  "is_partitioned" : 1,
  "director_table" : "dir_2",
  "director_key" : "dep_id"
}

{ "table" : "dep_2_1",
  "is_partitioned" : 1,
  "director_table" : "dir_2",
  "director_key" : "dep_id"
  "latitude_key" : "dep_coord_ra",
  "longitude_key" : "dep_coord_dec"
}

{ "table" : "dir_3",
  "is_partitioned" : 1,
  "director_table" : "",
  "director_key" : "objectId",
  "latitude_key" : "ra",
  "longitude_key" : "dec"
}

No dependents for the director table

Note

The attributes chunk_id_key and sub_chunk_id_key were required in older versions of the API and may still be present in JSON configurations. However, they are no longer needed for registering tables during ingest. The role-to-column mapping for these attributes is now predefined in the Ingest system implementation. The mapping is presented below:

role	column
`chunk_id_key`	`chunkId`
`sub_chunk_id_key`	`subChunkId`

If any of these attributes are found in a configuration, their definitions will be ignored.