Dynamic modification of schemas in streaming databases

摘要

A method for dynamically modifying a database schema in a streaming database management system receives a new database schema, compares the new schema to an existing schema, identifies the differences between the new schema and the existing schema, and applies the identified differences to the database in a single transaction, thereby producing a database organized according to the new database schema.

主权项

1. A method for dynamically modifying a database schema in a streaming database management system, the method comprising:
receiving a new database schema, wherein upon receipt the new database schema is determined to be valid; comparing the new database schema to an existing database schema of a database in the streaming database management system, the database having a plurality of data streams as inputs; identifying differences between the new database schema and the existing database schema based on the comparing; determining that a particular data stream fits in the existing database schema and does not fit into the new database schema; deleting the particular data stream; providing an end-of-data indication to one or more applications using the deleted stream; re-creating the particular data stream using a new identifier upon a determination that the particular data stream is modified; instantiating a conversion model of the new database schema; copying data of the database, with the existing database schema, into the conversion model; converting the copied data into a format compatible with the new database schema; modifying the database in accordance with the new database schema in a single transaction, wherein a plurality of modifications to the existing database schema are applied as a single transaction upon successful compilation of the each of the plurality of modifications, and none of the plurality of modifications of the dynamic modification are applied upon unsuccessful compilation of any of the plurality of modifications to the existing database schema; and copying the converted data from the conversion model to the modified database, wherein data corresponding to the particular data stream is not stored in the modified database.