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•The following table shows the maximum lengths for string attribute values. 

<img src='content_image/733642.jpg'>

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"]]’; 

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 incorporates these changes to the specification: 

•Only the <horz cs>  production rule is implemented (that is, geographic and projected SRSs). 

•There is an optional, nonstandard <authority>  clause for <parameter> . This makes it possible to recognize projection parameters by authority instead of name. 

•The specification does not make AXIS  clauses mandatory in GEOGCS  spatial reference system definitions. However, if there are no AXIS  clauses, MySQL cannot determine whether a definition has axes in latitude-longitude order or longitude-latitude order. MySQL enforces the nonstandard requirement that each GEOGCS  definition must include two AXIS  clauses. One must be NORTH  or SOUTH , and the other EAST  or WEST . The AXIS  clause order determines whether the definition has axes in latitude-longitude order or longitude-latitude order. 

•SRS definitions may not contain newlines. 

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 13.7, “Supported Spatial Reference System Projection Methods”  and Table 13.8, “Spatial Reference System Projection Parameters” . 

For additional information about writing SRS definitions for MySQL, see Geographic Spatial Reference Systems in MySQL 8.0 and Projected Spatial Reference Systems in MySQL 8.0 

The following table shows the projection methods that MySQL supports. MySQL permits unknown projection methods but cannot check the defintion for mandatory paramters and cannot convert spatial 

