compare.py 文件源码

def _compare_type(schema, tname, cname, conn_col,
                            metadata_col, diffs,
                            autogen_context):

    conn_type = conn_col.type
    metadata_type = metadata_col.type
    if conn_type._type_affinity is sqltypes.NullType:
        log.info("Couldn't determine database type "
                    "for column '%s.%s'", tname, cname)
        return
    if metadata_type._type_affinity is sqltypes.NullType:
        log.info("Column '%s.%s' has no type within "
                        "the model; can't compare", tname, cname)
        return

    isdiff = autogen_context['context']._compare_type(conn_col, metadata_col)

    if isdiff:

        diffs.append(
            ("modify_type", schema, tname, cname,
                    {
                        "existing_nullable": conn_col.nullable,
                        "existing_server_default": conn_col.server_default,
                    },
                    conn_type,
                    metadata_type),
        )
        log.info("Detected type change from %r to %r on '%s.%s'",
            conn_type, metadata_type, tname, cname
        )