Create a spatial column

seekdb allows you to create a spatial column using the CREATE TABLE or ALTER TABLE statement.

To create a table with spatial columns using the CREATE TABLE statement, see the following syntax example:

CREATE TABLE geom (g GEOMETRY);

To add or remove spatial columns in an existing table using the ALTER TABLE statement, see the following syntax example:

ALTER TABLE geom ADD pt POINT;
ALTER TABLE geom DROP pt;

Examples:

obclient> CREATE TABLE geom (
    p POINT SRID 0,
    g GEOMETRY NOT NULL SRID 4326
);
Query OK, 0 rows affected

The following constraints apply when creating spatial columns:

You can explicitly specify an SRID when defining a spatial column. If no SRID is defined on the column, the optimizer will not select the spatial index during queries, but index records will still be generated during insert/update operations.
A spatial index can be defined on a spatial column only after specifying the NOT NULL constraint and an SRID. In other words, only columns with a defined SRID can use spatial indexes.
Once an SRID is defined on a spatial column, attempting to insert values with a different SRID will result in an error.

The following constraints apply to SRID: