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.