>>> Tom Lane <[EMAIL PROTECTED]> wrote: > I was kinda wondering about something closer to the TOAST model, where > a blob is only referenceable from a value that's in a table field; > and that value encapsulates the "name" of the blob in some way that > needn't even be user-visible. This'd greatly simplify the > cleanup-dead-objects problem, and we could avoid addressing the > permissions problem at all, since regular SQL permissions on the table > would serve fine. But it's not clear what regular SQL fetch and update > behaviors should be like for such a thing. (Fetching or storing the > whole blob value is right out, IMHO.) ISTR hearing of concepts roughly > like this in other DBs --- does it ring a bell for anyone? It'd probably be good to have methods parallel to the JDBC API within the implementation. http://java.sun.com/javase/6/docs/api/java/sql/Blob.html http://java.sun.com/javase/6/docs/api/java/sql/Clob.html http://java.sun.com/javase/6/docs/api/java/sql/NClob.html http://java.sun.com/javase/6/docs/api/java/sql/ResultSet.html#getBlob(int) http://java.sun.com/javase/6/docs/api/java/sql/ResultSet.html#getClob(int) http://java.sun.com/javase/6/docs/api/java/sql/ResultSet.html#getNClob(int) http://java.sun.com/javase/6/docs/api/java/sql/ResultSet.html#updateBlob(int,%20java.sql.Blob) http://java.sun.com/javase/6/docs/api/java/sql/ResultSet.html#updateBlob(int,%20java.io.InputStream) http://java.sun.com/javase/6/docs/api/java/sql/ResultSet.html#updateBlob(int,%20java.io.InputStream,%20long) (similar for CLOB & NCLOB) Reading a blob value gives you an object which lets you perform the stream-based operations against the blob. To set a blob value on an insert, you prepare a statement and then link the stream to the blob -- the insertRow method sucks the data from the stream. To set a blob on an update, you use an updateable cursor (or maybe a prepared statement) to do the same. You can set a lob from another lob directly in SQL I assume we'd want to support streams directly inline in the protocol, as well as support functions to convert between datums and streams (for, say, tiny little 2MB or 10MB values), and files and streams (kinda like COPY). -Kevin
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