194 lines
6.5 KiB
Tcl
194 lines
6.5 KiB
Tcl
# tdbcmysql.tcl --
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#
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# Class definitions and Tcl-level methods for the tdbc::mysql bridge.
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#
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# Copyright (c) 2008 by Kevin B. Kenny
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# See the file "license.terms" for information on usage and redistribution
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# of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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#
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# RCS: @(#) $Id: tdbcmysql.tcl,v 1.47 2008/02/27 02:08:27 kennykb Exp $
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#
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#------------------------------------------------------------------------------
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package require tdbc
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::namespace eval ::tdbc::mysql {
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namespace export connection datasources drivers
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}
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#------------------------------------------------------------------------------
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#
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# tdbc::mysql::connection --
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#
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# Class representing a connection to a database through MYSQL.
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#
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#-------------------------------------------------------------------------------
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::oo::class create ::tdbc::mysql::connection {
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superclass ::tdbc::connection
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# The constructor is written in C. It takes alternating keywords
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# and values pairs as its argumenta. (See the manual page for the
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# available options.)
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variable foreignKeysStatement
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# The 'statementCreate' method delegates to the constructor of the
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# statement class
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forward statementCreate ::tdbc::mysql::statement create
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# The 'columns' method returns a dictionary describing the tables
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# in the database
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method columns {table {pattern %}} {
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# To return correct lengths of CHARACTER and BINARY columns,
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# we need to know the maximum lengths of characters in each
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# collation. We cache this information only once, on the first
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# call to 'columns'.
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if {[my NeedCollationInfo]} {
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my SetCollationInfo {*}[my allrows -as lists {
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SELECT coll.id, cs.maxlen
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FROM INFORMATION_SCHEMA.COLLATIONS coll,
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INFORMATION_SCHEMA.CHARACTER_SETS cs
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WHERE cs.CHARACTER_SET_NAME = coll.CHARACTER_SET_NAME
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ORDER BY coll.id DESC
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}]
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}
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return [my Columns $table $pattern]
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}
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# The 'preparecall' method gives a portable interface to prepare
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# calls to stored procedures. It delegates to 'prepare' to do the
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# actual work.
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method preparecall {call} {
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regexp {^[[:space:]]*(?:([A-Za-z_][A-Za-z_0-9]*)[[:space:]]*=)?(.*)} \
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$call -> varName rest
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if {$varName eq {}} {
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my prepare "CALL $rest"
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} else {
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my prepare \\{:$varName=$rest\\}
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}
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}
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# The 'init', 'begintransaction', 'commit, 'rollback', 'tables'
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# 'NeedCollationInfo', 'SetCollationInfo', and 'Columns' methods
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# are implemented in C.
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# The 'BuildForeignKeysStatements' method builds a SQL statement to
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# retrieve the foreign keys from a database. (It executes once the
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# first time the 'foreignKeys' method is executed, and retains the
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# prepared statements for reuse.) It is slightly nonstandard because
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# MYSQL doesn't name the PRIMARY constraints uniquely.
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method BuildForeignKeysStatement {} {
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foreach {exists1 clause1} {
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0 {}
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1 { AND fkc.REFERENCED_TABLE_NAME = :primary}
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} {
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foreach {exists2 clause2} {
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0 {}
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1 { AND fkc.TABLE_NAME = :foreign}
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} {
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set stmt [my prepare "
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SELECT rc.CONSTRAINT_SCHEMA AS \"foreignConstraintSchema\",
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rc.CONSTRAINT_NAME AS \"foreignConstraintName\",
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rc.UPDATE_RULE AS \"updateAction\",
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rc.DELETE_RULE AS \"deleteAction\",
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fkc.REFERENCED_TABLE_SCHEMA AS \"primarySchema\",
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fkc.REFERENCED_TABLE_NAME AS \"primaryTable\",
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fkc.REFERENCED_COLUMN_NAME AS \"primaryColumn\",
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fkc.TABLE_SCHEMA AS \"foreignSchema\",
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fkc.TABLE_NAME AS \"foreignTable\",
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fkc.COLUMN_NAME AS \"foreignColumn\",
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fkc.ORDINAL_POSITION AS \"ordinalPosition\"
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FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS rc
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INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE fkc
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ON fkc.CONSTRAINT_NAME = rc.CONSTRAINT_NAME
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AND fkc.CONSTRAINT_SCHEMA = rc.CONSTRAINT_SCHEMA
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WHERE 1=1
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$clause1
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$clause2
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"]
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dict set foreignKeysStatement $exists1 $exists2 $stmt
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}
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}
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}
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}
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#------------------------------------------------------------------------------
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#
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# tdbc::mysql::statement --
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#
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# The class 'tdbc::mysql::statement' models one statement against a
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# database accessed through an MYSQL connection
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#
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#------------------------------------------------------------------------------
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::oo::class create ::tdbc::mysql::statement {
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superclass ::tdbc::statement
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# The 'resultSetCreate' method forwards to the constructor of the
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# result set.
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forward resultSetCreate ::tdbc::mysql::resultset create
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# Methods implemented in C:
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#
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# constructor connection SQLCode
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# The constructor accepts the handle to the connection and the SQL code
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# for the statement to prepare. It creates a subordinate namespace to
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# hold the statement's active result sets, and then delegates to the
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# 'init' method, written in C, to do the actual work of preparing the
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# statement.
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# params
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# Returns descriptions of the parameters of a statement.
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# paramtype paramname ?direction? type ?precision ?scale??
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# Declares the type of a parameter in the statement
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}
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#------------------------------------------------------------------------------
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#
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# tdbc::mysql::resultset --
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#
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# The class 'tdbc::mysql::resultset' models the result set that is
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# produced by executing a statement against an MYSQL database.
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#
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#------------------------------------------------------------------------------
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::oo::class create ::tdbc::mysql::resultset {
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superclass ::tdbc::resultset
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# Methods implemented in C include:
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# constructor statement ?dictionary?
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# -- Executes the statement against the database, optionally providing
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# a dictionary of substituted parameters (default is to get params
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# from variables in the caller's scope).
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# columns
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# -- Returns a list of the names of the columns in the result.
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# nextdict
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# -- Stores the next row of the result set in the given variable in
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# the caller's scope as a dictionary whose keys are
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# column names and whose values are column values, or else
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# as a list of cells.
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# nextlist
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# -- Stores the next row of the result set in the given variable in
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# the caller's scope as a list of cells.
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# rowcount
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# -- Returns a count of rows affected by the statement, or -1
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# if the count of rows has not been determined.
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}
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