Ubuntu Manpage: tdbc::odbc - TDBC-ODBC bridge

Provided by: tcl8.6-tdbc-odbc_1.1.7-1build1_amd64

NAME

       tdbc::odbc - TDBC-ODBC bridge

SYNOPSIS

       package require tdbc::odbc 1.0

       tdbc::odbc::connection create db connectionString ?-option value...?
       tdbc::odbc::connection new connectionString ?-option value...?

       tdbc::odbc::datasources ?-system|-user?

       tdbc::odbc::drivers

       tdbc::odbc::datasource command driverName ?keyword-value?...
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DESCRIPTION

The tdbc::odbc driver provides a database interface that conforms to Tcl DataBase Connectivity (TDBC) and
allows a Tcl script to connect to any SQL database presenting an ODBC interface. It is also provided as
a worked example of how to write a database driver in C, so that driver authors have a starting point for
further development.

Connection to an ODBC database is established by invoking tdbc::odbc::connection create, passing it the
name to be used as a connection handle, followed by a standard ODBC connection string. As an alternative,
tdbc::odbc::connection new may be used to create a database connection with an automatically assigned
name. The return value from tdbc::odbc::connection new is the name that was chosen for the connection
handle.

The connection string will include at least a DRIVER or DSN keyword, and may include others that are
defined by a particular ODBC driver. (If the local ODBC system supports a graphical user interface, the
-parent option (see below) may allow calling tdbc::odbc::connection create with an empty connection
string.)

The side effect of tdbc::odbc::connection create is to create a new database connection.. See
tdbc::connection(3tcl) for the details of how to use the connection to manipulate a database.

In addition to a standard TDBC interface, tdbc::odbc supports three additional ccommands. The first of
these, tdbc::odbc::datasources, which returns a Tcl list enumerating the named data sources available to
the program (for connection with the DSN keyword in the connection string). The result of
tdbc::odbc::datasources may be constrained to only system data sources or only user data sources by
including the -system or -user options, respectively.

The tdbc::odbc::drivers command returns a dictionary whose keys are the names of drivers available for
the DRIVER keyword in the connection string, and whose values are descriptions of the drivers.

The tdbc::odbc::datasource command allows configuration of named data sources on those systems that
support the ODBC Installer application programming interface. It accepts a command, which specifies the
operation to be performed, the name of a driver for the database in question, and a set of keyword-value
pairs that are interpreted by the given driver. The command must be one of the following:

add Adds a user data source. The keyword-value pairs must include at least a DSN option naming the
data source

add_system
Adds a system data source. The keyword-value pairs must include at least a DSN option naming the
data source

configure
Configures a user data source. The keyword-value pairs will usually include a DSN option naming
the data source. Some drivers will support other options, such as the CREATE_DB option to the
Microsoft Access driver on Windows.

configure_system
Configures a system data source.

remove Removes a user data source. The keyword-value pairs must include a DSN option specifying the data
source to remove.

remove_system
Removes a system data source. The keyword-value pairs must include a DSN option specifying the
data source to remove.

CONNECTION OPTIONS

       The  tdbc::odbc::connection  create  object  command  supports  the  -encoding, -isolation, -readonly and
       -timeout options common to all TDBC drivers. The -encoding option will  succeed  only  if  the  requested
       encoding is the same as the system encoding; tdbc::odbc does not attempt to specify alternative encodings
       to an ODBC driver. (Some drivers accept encoding specifications in the connection string.)

       In  addition,  if Tk is present in the requesting interpreter, and the local system's ODBC driver manager
       supports a graphical user interface, the tdbc::odbc::connection create object command supports a  -parent
       option, whose value is the path name of a Tk window. If this option is specified, and a connection string
       does  not  specify  all  the  information needed to connect to an interface, the ODBC driver manager will
       display a dialog box to request whatever additional information is required. The  requesting  interpreter
       will block until the user dismisses the dialog, at which point the connection is made.

EXAMPLES

       Sincs ODBC connection strings are driver specific, it is often difficult to find the documentation needed
       to  compose them. The following examples are known to work on most Windows systems and provide at least a
       few useful things that a program can do.

              tdbc::odbc::connection create db \
                  "DSN={PAYROLL};UID={aladdin};PWD={Sesame}"
       Connects to a named data source "PAYROLL", providing "aladdin" as a user name and "Sesame" as a password.
       Uses db as the name of the connection.

              set connString {DRIVER={Microsoft Access Driver (*.mdb)};}
              append connString {FIL={MS Access}\;}
              append connString {DBQ=} \
                  [file nativename [file normalize $fileName]]
              tdbc::odbc::connection create db2 -readonly 1 $connString
       Opens a connection to a Microsoft Access database file whose name is in $fileName. The database is opened
       in read-only mode. The resulting connection is called "db2".

              tdbc::odbc::connection create db3 \
                  "DRIVER=SQLite3;DATABASE=$fileName"
       Opens a connection to a SQLite3 database whose name is in "$fileName".

              tdbc::odbc::datasource add \
                  {Microsoft Access Driver (*.mdb)} \
                  DSN=MyTestDatabase \
                  DBQ=[file native [file normalize $fileName]]
       Creates a new user data source with the name, "MyTestDatabase" bound to a  Microsoft  Access  file  whose
       path  name  is  in  "$fileName".  No  connection  is  made  to  the  data  source until the program calls
       tdbc::odbc::connection create.

              tdbc::odbc::datasource configure \
                  {Microsoft Access Driver (*.mdb)} \
                  CREATE_DB=[file native [file normalize $fileName]] \
                  General
       Creates a new, empty Microsoft Access database in the file identified by "$fileName".  No  connection  is
       made to the database until the program calls tdbc::odbc::connection create.

ADDITIONAL CONNECTION METHODS

       In  addition  to  the usual methods on the tdbc::connection(3tcl) object, connections to an ODBC database
       support one additional method:

       $connection
              This method takes the given driver-native SQL code sqlStatement and evaluates it without preparing
              it. The statement is not tokenized and must not contain variable  substitutions.   Evaluating  the
              sqlStatement  produces  a result set of zero or more rows.  The result of the command is a list of
              dictionaries, with one list element per row in the result set (in a similar  format  to  the  list
              returned  by  $connection  allrows -as dicts).  This command is not recommended for anything where
              the usual prepare or preparecall methods work correctly. It is provided so  that  data  management
              language  statements  that  are  not  implemented  by the driver's prepared statement API (such as
              CREATE DATABASE or CREATE PROCEDURE),  or  that  contain  characters  that  are  reserved  by  the
              tokenizer, can be executed.

KEYWORDS

       TDBC, SQL, ODBC, database, connectivity, connection

COPYRIGHT

       Copyright (c) 2008 by Kevin B. Kenny.

Tcl                                                    8.6                                      tdbc::odbc(3tcl)