ST_Curve

注:

仅 Oracle 和 SQLite

定义

ST_Curve 基于可识别的文本表示来构造曲线要素。

语法

Oracle

sde.st_curve (wkt clob, srid integer)

SQLite

st_curve (wkt text, srid int32)

返回类型

ST_LineString

示例

本示例使用曲线几何创建表，向其中插入值，然后选择一个要素。

Oracle

CREATE TABLE curve_test (
 id integer,
 geometry sde.st_curve
);

INSERT INTO CURVE_TEST VALUES (
 1910,
 sde.st_curve ('linestring (33 2, 34 3, 35 6)', 4326)
); 

SELECT id, sde.st_astext (geometry) CURVE
 FROM CURVE_TEST;

ID     CURVE

1110   LINESTRING (33.00000000 2.00000000, 34.00000000 3.00000000,
              35.00000000 6.00000000)

SQLite

CREATE TABLE curve_test (
 id integer primary key autoincrement not null
);

SELECT AddGeometryColumn(
 NULL,
 'curve_test',
 'geometry',
 4326,
 'linestring',
 'xy',
 'null'
);

INSERT INTO CURVE_TEST (geometry) VALUES (
 st_curve ('linestring (33 2, 34 3, 35 6)', 4326)
); 

SELECT id, st_astext (geometry) 
 AS curve
 FROM curve_test;

id     curve

1   LINESTRING (33.00000000 2.00000000, 34.00000000 3.00000000,
       35.00000000 6.00000000)