13. The system of claim 11 , wherein the second policy specifies the policy expressions corresponding to the second policy to evaluate the one or more second properties comprising the connection characteristics of a database connection for the request to execute the SQL query comprising one of the following: identification of an authenticated user, a name of the database, a character set sent by the client and client's capabilities.
11. A system for selecting by an intermediary device a database from a plurality of databases to forward a structured query language (SQL) query request based on a property of the SQL request, the system comprising: a device intermediary to a plurality of clients and a plurality of databases, wherein the device establishes a plurality of server-side connections to the plurality of databases, the device establishing a pool of server-side connections to each database of the plurality of databases; a database proxy of the device receiving from a client of the plurality of clients, a request to execute a structured query language (SQL) query included in the request; a policy engine of the database proxy parsing the SQL query to identify one or more first properties of the SQL query that are exposed using policy expressions corresponding to a first policy for selecting a database to execute the SQL query, evaluating, responsive to the first policy, the one or more first properties of the SQL query to select a database to execute the SQL query, the one or more first properties of the SQL query identifying an action to be taken on a database, parsing the SQL query to identify one or more second properties of the SQL query that are exposed using policy expressions corresponding to a second policy for selecting a server-side connection of the pool of server-side connections over which to forward the SQL query to the database, and evaluating, responsive to the second policy, one or more second properties of the SQL query to select a server-side connection of the pool of server-side connections over which to forward the SQL query to the selected database, the one or more second properties identifying connection characteristics of a database connection; and wherein the database proxy selects a database from the plurality of databases based on a result of evaluation of the one or more first properties of the SQL query, selects the server-side connection of the pool of server-side connections based on a result of evaluation of the one or more second properties of the SQL query and forwards the SQL query to the selected database via the server-side connection of the plurality of server-side connections.