Catalog#

Catalog Manager#

Explanation for developers on how to use the eva catalog_manager.

CatalogManager class that provides a set of services to interact with a database that stores metadata about tables, columns, and user-defined functions (UDFs). Information like what is the data type in a certain column in a table, type of a table, its name, etc.. It contains functions to get, insert and delete catalog entries for Tables, UDFs, UDF IOs, Columns and Indexes.

This data is stored in the eva_catalog.db file which can be found in ~/.eva/<version>/ folder.

Catalog manager currently has 5 services in it:

TableCatalogService()
ColumnCatalogService()
UdfCatalogService()
UdfIOCatalogService()
IndexCatalogService()

Catalog Services#

This class provides functionality related to a table catalog, including inserting, getting, deleting, and renaming table entries, as well as retrieving all entries. e.g. the TableCatalogService contains code to get, insert and delete a table.

Catalog Models#

These contain the data model that is used by the catalog services. Each model represents a table in the underlying database.

Catalog Diagram