Connect a legacy application to Database using Web Service

I want to develop a system in which all network communications are via web services. My problem is I used some legacy applications.

These applications need to connect to a database. My problem is I don't want to let them to use native, binary connection to database.

I was looking for a solution.

Something like a virtual database that is a proxy process which accept connections, then transfer these connections to Web Service and connect to开发者_C百科 database.

I want to not change any code, in the best case just connection string.

Currently I'm using Linux and thinking about using PostgreSQL Database but any solution will be appreciated.

Assuming that all the legacy applications can either be configured to use a different database connection (connection string, host name, whatever), then you need a proxy database server.

This will only work if the protocol between the legacy applications and the database is well-documented.

Also, this service will be 100% specific to the database being used. All of your web service operations will need to be at the same level as the database operations on the database protocol. This will not be very high-level.

This is far too much effort, will be supported entirely by you, and will not be worth it.

You are describing one of the use cases that went into the design of Service-oriented architecture (SOA). In a SOA environment all these components are loosely coupled via service providers. You can have legacy applications, business rule engines, and back end databases all communicating via defined services.