CONVERT_IMPLICIT插入地理數據類型到一個地理數據類型列時

TSQL MSSQL 2008R2CONVERT_IMPLICIT插入地理數據類型到一個地理數據類型列時

爲什麼以下進行CONVERT_IMPLICIT即地理數據類型轉換成地理數據類型？

DECLARE @xPolygon NVARCHAR(MAX) = '53.835134 -2.474670, 53.812436 -0.288391, 52.417944 -0.090637, 52.270286 -3.018494, 53.835134 -2.474670' 

IF OBJECT_ID('#xSpatialTable') IS NOT NULL 
    DROP TABLE #xSpatialTable; 
CREATE TABLE #xSpatialTable (
    id   INT IDENTITY (1,1) CONSTRAINT PK_xSpatialTable PRIMARY KEY 
    ,GeogCol1 GEOGRAPHY 
    ,GeogCol2 AS GeogCol1.STAsText() 
); 

INSERT INTO #xSpatialTable (GeogCol1) 
VALUES (GEOGRAPHY::STPolyFromText('POLYGON((' + @xPolygon + '))', 4326)); 

IF OBJECT_ID('#xSpatialTable') IS NOT NULL 
    DROP TABLE #xSpatialTable;

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CONVERT_IMPLICIT（地理，[地理] :: STPolyFromText（（N'POLYGON（（ '+ [@ xPolygon]）+ N'））」，（4326）），0）

同樣這裏也適用

DECLARE @xLongitude FLOAT = 53.835134 
DECLARE @xLatitude FLOAT = -2.474670 

IF OBJECT_ID('#xSpatialTable') IS NOT NULL 
    DROP TABLE #xSpatialTable; 
CREATE TABLE #xSpatialTable (
    id   INT IDENTITY (1,1) CONSTRAINT PK_xSpatialTable PRIMARY KEY 
    ,GeogCol1 GEOGRAPHY 
    ,GeogCol2 AS GeogCol1.STAsText() 
); 

INSERT INTO #xSpatialTable (GeogCol1) 
VALUES (GEOGRAPHY::STGeomFromText('POINT(' + CAST(@xLongitude AS NVARCHAR(20)) + ' ' + CAST(@xLatitude AS NVARCHAR(20)) + ')', 4326)); 

IF OBJECT_ID('#xSpatialTable') IS NOT NULL 
    DROP TABLE #xSpatialTable;

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