Scope

This repo contains:

• Postgres Wire compatible server able to use arbitrary JDBC driver. E.G. if you installed the H2 driver you can send H2 dialect queries
• ADO Data provider for the aforementioned server
• Some compatibility tests to use the standard ODBC Postgres driver with the server

In the future

• EF drivers
• NHibernate dialects

Based on

• https://segmentfault.com/a/1190000017136059
• https://gavinray97.github.io/blog/postgres-wire-protocol-jdk-21
• https://www.postgresql.org/docs/current/protocol-message-formats.html
• https://www.postgresql.org/docs/current/protocol-error-fields.html
• https://www.postgresql.org/message-id/AANLkTikkkxN+-UUiGVTzj8jdfS4PdpB8_tDONMFHNqHk@mail.gmail.com

How it works

For testing it, first install (if you are interested) the Postgres SQL ODBC driver

On the properties of the ODBC driver, set "Parse statements" to false

Jdbc

• Just open the jdbc-server project and run the relevant tests

Ado

• Start the main for the JDBC server
• Run the tests

ODBC

• Start the main for the JDBC server
• Run the tests

Command line

• In pgsql folder you can find the command line client. To make an example just run

  psql -h localhost -p 5432 -U postgres

And then in the prompt

create table if not exists test(id int, name varchar);
insert into test values(1,'test1');
insert into test values(2,'test2');
select * from test;

Assorted Weirdness

ODBC

• It does some queries to optimize probably the conversions. Luckily a simple "empty answer" can solve this
• During the startup there are many properties needed by the driver. If they are not shown everything crashes. Horribly.
  • Timezone
  • Codepage
• Internal queries are used through the "Simple" query protocol
• The Bind Message seems to not contain the output parameters at all
• The flow starts with the StartupMessage

JDBC

• The Bind Message seems to not contain the output parameters at all
• Named parameters are only a convention
• Batched queries are allowed only through use multiple statements
• The flow starts with the SSLNegotiation

ADO, my implementation

• Named parameters are only a convention
• The "old stile batched queries" are now deprecated but they "mostly" works