MySQL空间数据库学习

MySQL支持的空间数据格式有WKT,WKB,数据类型有:POINT、LINESTRING、POLYGON、MULTIPOINT、MULTILINESTRING、MULTIPOLYGON、GEOMETRYCOLLECTION。

例如WKT格式如下:

POINT(15, 20)
LINESTRING(0 0, 10 10, 20 25, 50 60)
POLYGON((0 0,10 0,10 10,0 10,0 0),(5 5,7 5,7 7,5 7, 5 5))
MULTIPOINT(0 0, 20 20, 60 60)
MULTILINESTRING((10 10, 20 20), (15 15, 30 15))
MULTIPOLYGON(((0 0,10 0,10 10,0 10,0 0)),((5 5,7 5,7 7,5 7, 5 5)))
GEOMETRYCOLLECTION(POINT(10 10), POINT(30 30), LINESTRING(15 15, 20 20))

WKB格式则使用BLOB类型。


创建空间数据库:

create database spatialtest;

创建可以存储点、线、面的空间数据表:

create table t_geo(geo geometry);

创建存储点的空间数据表:

create table t_pt(pt point);


创建存储线的空间数据表:

create table t_line(line linestring);

创建存储面的空间数据表:

create table t_polygon(poly polygon);

插入WKT数据测试:

insert into t_geo(geo) values(GeometryFromText('POINT(0 0)'));
insert into t_geo(geo) values(GeometryFromText('POLYGON((5 0.0,0.0 -5,-5 0,0.0 5,5 0.0))'));
insert into t_geo(geo) values(GeometryFromText('LINESTRING(10 0, 5 5, 9 8, -10 -10)'));
insert into t_pt(pt) values(GeometryFromText('POINT(0 2)'));
insert into t_line(line) values(GeometryFromText('LINESTRING(10 0, 5 5, 9 8, -10 -10)'));
insert into t_polygon(poly) values(GeometryFromText('POLYGON((5 0.0,0.0 -5,-5 0,0.0 5,5 0.0))'));

查询数据测试:

select Asbinary(pt) from t_pt;
select Astext(pt) from t_pt;


给表创建空间索引:

alter table t_pt add spatial index(pt);

返回错误:

The used table type doesn't support SPATIAL indexes

查询文档发现: Before MySQL 5.0.16, these features are available for  MyISAM  tables only. As of MySQL 5.0.16,  InnoDB NDB , BDB , and  ARCHIVE  also support spatial features.

所以需要执行如下语句:

ALTER TABLE `spatialtest`.`t_geo` ENGINE = MyISAM ;

然后在执行创建空间索引则返回成功。


参考:http://dev.mysql.com/doc/refman/5.0/en/spatial-extensions.html




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