//! Simple schema representation for migration state
traitSchemas{/// Returns the name of a database
fnname(&self)-> String;/// Returns a list of all tables in a database
fntables(&self)->Vec<String>;/// Returns a list of all column names and types
fncolumns(&self, table:&str)->Vec<(String, Column)>;}traitColumn{/// Get the type of column in SQL specific terms
fntype(&self)-> String;}// Describe the current state of a database to apply a migration to
structSchema{db_name: String,
columns:Vec<String>,
}implSchema{}