Oracle function real_st_astext，解决ArcSDE中st_astext函数返回字符串结构异常问题

项目过程中发现在Oracle中调用ArcSDE的st_astext函数返回ST_Geometry类型字段的WKT文本有时空间类型前缀没有返回，例如一个点的经度为113.4，纬度为30.6，调用st_astext函数正常返回就应该是“POINT(113.4 30.6)”，但有时返回的是“(113.4 30.6)”，缺少POINT前缀，以下real_st_astext函数可解决该问题。

create or replace function real_st_astext(geom1 in clob) return clob is
  geometry clob;
  tempGeom clob;
  geom clob;
  lonlatStr clob;--第一段经纬度字符串
  firstStr clob;--第一个点的经纬度
  lastIndex int;--第一个点最后一次出现的游标
begin
  geom := trim(geom1);
  geom := replace(geom,'( ','(');
  geom := replace(geom,' (','(');
  geom := replace(geom,') ',')');
  geom := replace(geom,' )',')');
  geom := replace(geom,', ',',');
  geometry := upper(geom);
  if geom like '(((%' then
    geometry := 'MULTIPOLYGON' || geom;
  else
    if geom like '((%' then
      tempGeom := substr(geom, instr(geom, '((') + 2, length(geom));
      lonlatStr := substr(tempGeom, 0, instr(tempGeom, ')')-1);
      firstStr := trim(substr(lonlatStr, 0, instr(lonlatStr, ',')-1));
      lastIndex := instr(lonlatStr, firstStr, -1);
      if lastIndex = length(lonlatStr) - length(firstStr) + 1 then
        geometry := 'POLYGON '||geom;
      else
        geometry := 'MULTILINESTRING ' || geom;
      end if;
    else
      if geom like '(%' then
        if geom like '%,%' then
          geometry := 'LINESTRING' || geom;
        else
          geometry := 'POINT' || geom;
        end if;
      end if;
    end if;
  end if;
  return geometry;
end;