sqlalchemy_schemadisplay.py 文件源码

def create_schema_graph(tables=None, metadata=None, show_indexes=True, show_datatypes=True, font="Bitstream-Vera Sans",
    concentrate=True, relation_options={}, rankdir='TB'):
    relation_kwargs = {
        'fontsize':"7.0"
    }
    relation_kwargs.update(relation_options)

    if metadata is None and tables is not None and len(tables):
        metadata = tables[0].metadata
    elif tables is None and metadata is not None:
        if not len(metadata.tables):
            metadata.reflect()
        tables = list(metadata.tables.values())
    else:
        raise ValueError("You need to specify at least tables or metadata")

    graph = pydot.Dot(prog="dot",mode="ipsep",overlap="ipsep",sep="0.01",concentrate=str(concentrate), rankdir=rankdir)
    for table in tables:
        graph.add_node(pydot.Node(str(table.name),
            shape="plaintext",
            label=_render_table_html(table, metadata, show_indexes, show_datatypes),
            fontname=font, fontsize="7.0"
        ))

    for table in tables:
        for fk in table.foreign_keys:
            if fk.column.table not in tables:
                continue
            edge = [table.name, fk.column.table.name]
            is_inheritance = fk.parent.primary_key and fk.column.primary_key
            if is_inheritance:
                edge = edge[::-1]
            graph_edge = pydot.Edge(
                headlabel="+ %s"%fk.column.name, taillabel='+ %s'%fk.parent.name,
                arrowhead=is_inheritance and 'none' or 'odot' ,
                arrowtail=(fk.parent.primary_key or fk.parent.unique) and 'empty' or 'crow' ,
                fontname=font,
                #samehead=fk.column.name, sametail=fk.parent.name,
                *edge, **relation_kwargs
            )
            graph.add_edge(graph_edge)

# not sure what this part is for, doesn't work with pydot 1.0.2
#            graph_edge.parent_graph = graph.parent_graph
#            if table.name not in [e.get_source() for e in graph.get_edge_list()]:
#                graph.edge_src_list.append(table.name)
#            if fk.column.table.name not in graph.edge_dst_list:
#                graph.edge_dst_list.append(fk.column.table.name)
#            graph.sorted_graph_elements.append(graph_edge)
    return graph