Overcoming Challenges with MySQL Spatial Fields: A Story of Persistence

When working with spatial fields in MySQL, it can be frustrating to encounter errors and unexpected behavior. In this article, we'll explore one such challenge and how we overcame it.

We're using MemSQL V7.0, a popular open-source relational database management system that supports spatial data types like POINT. Our goal was to create a stored procedure that would generate spatial field data from lat and lng coordinates.

To achieve this, we created the following query:

```sql

UPDATE $table SET `geocode` = GeomFromText('POINT($place_lat $place_lng)') ON DUPLICATE KEY UPDATE `note`= '$note',`positive`=$positive;

```

However, when we tried to execute this query, we encountered an error. It seemed that the spatial field computation was not being done by MySQL as expected.

After some trial and error, we realized that the issue might be related to the way we were passing the spatial point data from PHP to MySQL. We had initially tried using parameterized queries, but it didn't seem to work as expected.

In our case, the problem was resolved by specifying the field names for only the fields we wanted returned. This change made a significant difference in the way many of our PHP scripts engaged with that table.

The Power of ON DUPLICATE KEY UPDATE

One of the most useful features of MySQL is the ability to perform updates on duplicate key values using the `ON DUPLICATE KEY UPDATE` clause. This allows us to update existing records rather than inserting new ones when a duplicate value is found.

In our case, we were trying to use this feature to update a record in our table based on its primary key (`id`). However, instead of updating the record, it was inserting a new one every time.

The solution was to modify the query to include the `ON DUPLICATE KEY UPDATE` clause correctly:

```sql

INSERT INTO $table (`id`, `geocode`) VALUES ($NTP_id, GeomFromText('POINT($place_lat $place_lng)')) ON DUPLICATE KEY UPDATE `note`= '$note',`positive`=$positive;

```

By including the `ON DUPLICATE KEY UPDATE` clause, we were able to update the existing record instead of inserting a new one.

In conclusion, working with spatial fields in MySQL can be challenging, but with persistence and creative problem-solving, you can overcome these challenges and achieve your goals. By using the `ON DUPLICATE KEY UPDATE` clause correctly, you can ensure that updates are performed on duplicate key values rather than inserting new records.

On duplicate key update