<html><head><title>Memory</title></head><bodybgcolor="#ffffff"><h1>Memory</h1>This driver implements read and write access layers of features containedentirely in memory. This is primarily useful as a high performance, and highlymalleable working data store. All update options, geometry types, andfield types are supported.<p>There is no way to open an existing Memory datastore. It must be createdwith CreateDataSource() and populated and used from that handle. When thedatastore is closed all contents are freed and destroyed. <p>The driver does not implement spatial or attribute indexing, so spatial andattribute queries are still evaluated against all features. Fetching featuresby feature id should be very fast (just an array lookup and feature copy).<p><h2>Creation Issues</h2>Any name may be used for a created datasource. There are no datasourceor layer creation options supported. Layer names need to be unique, butare not otherwise constrained.<p>Before GDAL 2.1, feature ids passed to CreateFeature() are preserved <i>unless</i> they exceed10000000 in which case they will be reset to avoid a requirement for anexcessively large and sparse feature array. Starting with GDAL 2.1, sparseIDs can be handled.<p>New fields can be added or removed to a layer that already has features. <p></body></html>