private static Set<Vertex> createSourceVertices(
      Map<String, Vertex> vertexCache, Collection<BaseColumnInfo> baseCols) {
    Set<Vertex> sources = new LinkedHashSet<Vertex>();
    if (baseCols != null && !baseCols.isEmpty()) {
      for(BaseColumnInfo col: baseCols) {
        Table table = col.getTabAlias().getTable();
        if (table.isTemporary()) {
          // Ignore temporary tables
          continue;
        }
        Vertex.Type type = Vertex.Type.TABLE;
        String tableName = Warehouse.getQualifiedName(table);
        FieldSchema fieldSchema = col.getColumn();
        String label = tableName;
        if (fieldSchema != null) {
          type = Vertex.Type.COLUMN;
          label = tableName + "." + fieldSchema.getName();
        }
        sources.add(getOrCreateVertex(vertexCache, label, type));
      }
    }
    return sources;
  }
Convert a list of columns to a set of vertices.
Use cached vertices if possible.
ql/src/java/org/apache/hadoop/hive/ql/hooks/LineageLogger.java