The following SQL can be used to list tables and column names

SQL server

select TABLE_CATALOG,
TABLE_SCHEMA,
TABLE_NAME,
COLUMN_NAME,
DATA_TYPE,
CHARACTER_MAXIMUM_LENGTH
from .information_schema.columns

Oracle

select OWNER,
TABLE_NAME,
COLUMN_NAME,
DATA_TYPE,
DATA_LENGTH
DATA_PRECISION
from ALL_tab_cols;