CREATE OR REPLACE SPATIAL REFERENCE SYSTEM
    srid srs_attribute ...

CREATE SPATIAL REFERENCE SYSTEM
    [IF NOT EXISTS]
    srid srs_attribute ...

srs_attribute: {
    NAME 'srs_name'
  | DEFINITION 'definition'
  | ORGANIZATION 'org_name' IDENTIFIED BY org_id
  | DESCRIPTION 'description'
}

srid, org_id: 32-bit unsigned integer

此语句创建一个空间参考系统(SRS)定义，并将其存储在数据字典中。它需要SUPER权限。生成的数据字典条目可以使用INFORMATION_SCHEMAST_SPATIAL_REFERENCE_SYSTEMS表查看。This statement creates a spatial reference system (SRS) definition and stores it in the data dictionary. It requires the SUPER privilege. The resulting data dictionary entry can be inspected using the INFORMATION_SCHEMA ST_SPATIAL_REFERENCE_SYSTEMS table.

SRID 值必须唯一，因此如果未指定OR REPLACE或IF NOT EXISTS，当存在具有给定srid值的 SRS 定义时，将发生错误。SRID values must be unique, so if neither OR REPLACE nor IF NOT EXISTS is specified, an error occurs if an SRS definition with the given srid value already exists.

使用CREATE OR REPLACE语法时，任何具有相同 SRID 值的现有 SRS 定义将被替换，除非该 SRID 值已被现有表中的某列使用。在这种情况下，将发生错误。例如：With CREATE OR REPLACE syntax, any existing SRS definition with the same SRID value is replaced, unless the SRID value is used by some column in an existing table. In that case, an error occurs. For example:

mysql> CREATE OR REPLACE SPATIAL REFERENCE SYSTEM 4326 ...;
ERROR 3716 (SR005): Can't modify SRID 4326. There is at
least one column depending on it.

要识别使用 SRID 的列，请使用此查询，并将 4326 替换为您尝试创建的定义的 SRID：To identify which column or columns use the SRID, use this query, replacing 4326 with the SRID of the definition you are trying to create:

SELECT * FROM INFORMATION_SCHEMA.ST_GEOMETRY_COLUMNS WHERE SRS_ID=4326;

使用 CREATE ... IF NOT EXISTS 语法时，任何具有相同 SRID 值的现有 SRS 定义都会导致新的定义被忽略，并且会出现警告。With CREATE ... IF NOT EXISTS syntax, any existing SRS definition with the same SRID value causes the new definition to be ignored and a warning occurs.

SRID 值必须在 32 位无符号整数的范围内，并具有以下限制：SRID values must be in the range of 32-bit unsigned integers, with these restrictions:

声明的属性必须满足以下条件：Attributes for the statement must satisfy these conditions:

这是一个 CREATE SPATIAL REFERENCE SYSTEM 语句的示例。DEFINITION 的值被分多行重新格式化以便于阅读。（为了语句合法，该值实际上必须写在一行上。）Here is an example CREATE SPATIAL REFERENCE SYSTEM statement. The DEFINITION value is reformatted across multiple lines for readability. (For the statement to be legal, the value actually must be given on a single line.)

CREATE SPATIAL REFERENCE SYSTEM 4120
NAME 'Greek'
ORGANIZATION 'EPSG' IDENTIFIED BY 4120
DEFINITION
  'GEOGCS["Greek",DATUM["Greek",SPHEROID["Bessel 1841",
  6377397.155,299.1528128,AUTHORITY["EPSG","7004"]],
  AUTHORITY["EPSG","6120"]],PRIMEM["Greenwich",0,
  AUTHORITY["EPSG","8901"]],UNIT["degree",0.017453292519943278,
  AUTHORITY["EPSG","9122"]],AXIS["Lat",NORTH],AXIS["Lon",EAST],
  AUTHORITY["EPSG","4120"]]';

SRS 定义的语法基于 OpenGIS Implementation Specification: Coordinate Transformation Services，版本 1.00，OGC 01-009，2001 年 1 月 12 日，第 7.2 节中定义的语法。该规范可在 http://www.opengeospatial.org/standards/ct 获取。The grammar for SRS definitions is based on the grammar defined in OpenGIS Implementation Specification: Coordinate Transformation Services, Revision 1.00, OGC 01-009, January 12, 2001, Section 7.2. This specification is available at http://www.opengeospatial.org/standards/ct.

MySQL 将这些更改纳入规范：MySQL incorporates these changes to the specification:

如果 SRS 定义为投影指定了一个权限代码（推荐使用），当定义缺少必需参数时会发生错误。在这种情况下，错误消息会指出问题所在。MySQL 支持的投影方法和必需参数列在 表 15.7，“支持的空间参考系统投影方法” 和 表 15.8，“空间参考系统投影参数” 中。If an SRS definition specifies an authority code for the projection (which is recommended), an error occurs if the definition is missing mandatory parameters. In this case, the error message indicates what the problem is. The projection methods and mandatory parameters that MySQL supports are shown in Table 15.7, “Supported Spatial Reference System Projection Methods” and Table 15.8, “Spatial Reference System Projection Parameters”.

下表显示了 MySQL 支持的投影方法。MySQL 允许未知投影方法，但无法检查定义中的必需参数，也无法将空间数据转换到未知投影或从未知投影转换。有关每种投影方法的详细工作原理（包括公式）的说明，请参见 EPSG 指导说明 7-2。The following table shows the projection methods that MySQL supports. MySQL permits unknown projection methods but cannot check the definition for mandatory parameters and cannot convert spatial data to or from an unknown projection. For detailed explanations of how each projection works, including formulas, see EPSG Guidance Note 7-2.

下表显示了 MySQL 识别的投影参数。识别主要依赖于权威代码。如果没有权威代码，MySQL 会回退到对参数名称的不区分大小写的字符串匹配。有关每个参数的详细信息，请通过代码在 EPSG 在线注册表 中查询。The following table shows the projection parameters that MySQL recognizes. Recognition occurs primarily by authority code. If there is no authority code, MySQL falls back to case-insensitive string matching on the parameter name. For details about each parameter, look it up by code in the EPSG Online Registry.