Create MultiTableMetadata.add_table method

[npatki]

Problem Description

As a user, I would like the ability to create multi table metadata using Python. Right now, this is only partially supported because i can add columns but not new tables.

Expected behavior

Create an add_table method for the MultiTableMetadata object. This will create an empty table, after which the user can use add_column to fill out the columns.

Parameters

• (required) table_name: A string with the name of the table to add

metadata.add_table(table_name='users')
metadata.add_column(column_name='user_id', sdtype='text', regex_format='U_[0-9]{4}')
metadata.add_column(column_name='age', sdtype='numerical')

Error Handling

Invalid Table Name: Table name must be a string and cannot be empty

metadata.add_table(table_name='')
Error: Invalid table name (''). The table name must be a non-empty string.

Repeated Table Name: The table name cannot already exist

# assume the 'users' table already exists
metadata.add_table(table_name='users')
Error: Cannot add a table named 'users' because it already exists in the metadata. Please choose a different name.

Validation: In metadata.validate() we should add another check to validate that all tables have at least 1 column

metadata.add_table(table_name='sessions')
metadata.validate()
Error: Table 'sessions' has 0 columns. Use 'add_column' to specify its columns.