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It is my hope that the following "patches" to libpgtcl get included in the next release. See the update to the README file to get a full description of the changes. This version of libpgtcl is completely interpreter-safe, implements the database connection handle as a channel (no events yet, but will make it a lot easier to do fileevents on it in the future), and supports the SQL "copy table to stdout" and "copy table from stdin" commands, with the I/O being from and to the connection handle. The connection and result handles are formatted in a way to make access to the tables more efficient.
39 lines
1.9 KiB
Plaintext
39 lines
1.9 KiB
Plaintext
libpgtcl is a library that implements Tcl commands for front-end
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clients to interact with the Postgresql 6.3 (and perhaps later)
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backends. See libpgtcl.doc for details.
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For an example of how to build a new tclsh to use libpgtcl, see the
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directory ../bin/pgtclsh
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Note this version is modified by NeoSoft to have the following additional
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features:
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1. Postgres connections are a valid Tcl channel, and can therefore
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be manipulated by the interp command (ie. shared or transfered).
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A connection handle's results are transfered/shared with it.
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(Result handles are NOT channels, though it was tempting). Note
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that a "close $connection" is now functionally identical to a
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"pg_disconnect $connection", although pg_connect must be used
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to create a connection.
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2. Result handles are changed in format: ${connection}.<result#>.
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This just means for a connection 'pgtcl0', they look like pgtcl0.0,
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pgtcl0.1, etc. Enforcing this syntax makes it easy to look up
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the real pointer by indexing into an array associated with the
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connection.
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3. I/O routines are now defined for the connection handle. I/O to/from
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the connection is only valid under certain circumstances: following
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the execution of the queries "copy <table> from stdin" or
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"copy <table> to stdout". In these cases, the result handle obtains
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an intermediate status of "PGRES_COPY_IN" or "PGRES_COPY_OUT". The
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programmer is then expected to use Tcl gets or read commands on the
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database connection (not the result handle) to extract the copy data.
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For copy outs, read until the standard EOF indication is encountered.
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For copy ins, puts a single terminator (\.). The statement for this
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would be
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puts $conn "\\." or puts $conn {\.}
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In either case (upon detecting the EOF or putting the `\.', the status
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of the result handle will change to "PGRES_COMMAND_OK", and any further
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I/O attempts will cause a Tcl error.
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