定义
ST_MLineFromWKB 以 ST_MultiLineString 类型的熟知二进制 (WKB) 表示和空间参考 ID 为输入参数,以创建 ST_MultiLineString 类型的对象。
语法
Oracle
sde.st_mlinefromwkb (wkb blob, srid integer)
sde.st_mlinefromwkb (wkb blob)
如果您未指定 SRID,则空间参考默认为 4326。
PostgreSQL
sde.st_mlinefromwkb (wkb bytea, srid integer)
SQLite
st_mlinefromwkb (wkb blob, srid int32)
st_mlinefromwkb (wkb blob)
如果您未指定 SRID,则空间参考默认为 4326。
返回类型
ST_MultiLineString
示例
本示例说明了如何使用 ST_MLineFromWKB 由熟知二进制表示创建多线串。几何是空间参考系统 4326 中的一个多线串。在本示例中,多线串存储在 sample_mlines 表的几何列中且 ID = 10,然后利用熟知二进制表示对 wkb 列进行更新(使用 ST_AsBinary 函数)。最后,ST_MLineFromWKB 函数用于从 wkb 列中返回多线串。sample_mlines 表具有一个几何列(用于存储多线串)和一个 wkb 列(用于存储多线串的 WKB 表示)。
SELECT 语句包含 ST_MLineFromWKB 函数,该函数用于从 wkb 列检索多线串。
Oracle
CREATE TABLE sample_mlines (
id integer,
geometry sde.st_geometry,
wkb blob
);
INSERT INTO SAMPLE_MLINES (id, geometry) VALUES (
10,
sde.st_multilinestring ('multilinestring ((61 2, 64 3, 65 6), (58 4, 59 5, 61 8), (69 3, 67 4, 66 7, 68 9))', 4326)
);
UPDATE SAMPLE_MLINES
SET wkb = sde.st_asbinary (geometry)
WHERE id = 10;
SELECT id, sde.st_astext (sde.st_mlinefromwkb (wkb,0)) MULTI_LINE_STRING
FROM SAMPLE_MLINES
WHERE id = 10;
ID MULTI_LINE_STRING
10 MULTILINESTRING ((61.00000000 2.00000000, 64.00000000 3.00000000, 65.00000000 6.00000000), (58.00000000 4.00000000, 59.00000000 5.00000000, 61.00000000 8.0000000), (69.00000000 3.00000000, 67.00000000 4.00000000, 66.00000000 7.00000000, 68.00000000 9.00000000 ))
PostgreSQL
CREATE TABLE sample_mlines (
id integer,
geometry sde.st_geometry,
wkb bytea);
INSERT INTO sample_mlines (id, geometry) VALUES (
10,
sde.st_multilinestring ('multilinestring ((61 2, 64 3, 65 6), (58 4, 59 5, 61 8), (69 3, 67 4, 66 7, 68 9))', 4326)
);
UPDATE sample_mlines
SET wkb = sde.st_asbinary (geometry)
WHERE id = 10;
SELECT id, sde.st_astext (sde.st_mlinefromwkb (wkb,4326))
AS MULTI_LINE_STRING
FROM sample_mlines
WHERE id = 10;
id multi_line_string
10 MULTI_LINE_STRING ((61 2, 64 3, 65 6), (58 4, 59 5,61 8), (69 3, 67 4, 66 7, 68 9 ))
SQLite
CREATE TABLE sample_mlines (
id integer,
wkb blob);
SELECT AddGeometryColumn (
NULL,
'sample_mlines',
'geometry',
4326,
'multilinestring',
'xy',
'null'
);
INSERT INTO sample_mlines (id, geometry) VALUES (
10,
st_multilinestring ('multilinestring ((61 2, 64 3, 65 6), (58 4, 59 5, 61 8), (69 3, 67 4, 66 7, 68 9))', 4326)
);
UPDATE sample_mlines
SET wkb = st_asbinary (geometry)
WHERE id = 10;
SELECT id, st_astext (st_mlinefromwkb (wkb,4326))
AS MULTI_LINE_STRING
FROM sample_mlines
WHERE id = 10;
id multi_line_string
10 MULTI_LINE_STRING ((61.00000000 2.00000000, 64.00000000 3.00000000, 65.00000000 6.00000000),
(58.00000000 4.00000000, 59.00000000 5.00000000, 61.00000000 8.00000000),
(69.00000000 3.00000000, 67.00000000 4.00000000, 66.00000000 7.00000000, 68.00000000 9.00000000 ))