| '\" |
| .\" tdbc_odbc.n -- |
| .\" |
| .\" Copyright (c) 2008 by Kevin B. Kenny. |
| .\" |
| .\" See the file "license.terms" for information on usage and redistribution of |
| .\" this file, and for a DISCLAIMER OF ALL WARRANTIES. |
| .TH "tdbc::odbc" n 8.6 Tcl "Tcl Database Connectivity" |
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| .. |
| .BS |
| .SH "NAME" |
| tdbc::odbc \- TDBC-ODBC bridge |
| .SH "SYNOPSIS" |
| package require \fBtdbc::odbc 1.0\fR |
| .sp |
| \fBtdbc::odbc::connection create\fR \fIdb\fR \fIconnectionString\fR ?\fI-option value...\fR? |
| .br |
| \fBtdbc::odbc::connection new\fR \fIconnectionString\fR ?\fI-option value...\fR? |
| .sp |
| \fBtdbc::odbc::datasources\fR ?\fB-system\fR|\fB-user\fR? |
| .sp |
| \fBtdbc::odbc::drivers\fR |
| .sp |
| \fBtdbc::odbc::datasource\fR \fIcommand\fR \fIdriverName\fR ?\fIkeyword\fR-\fIvalue\fR?... |
| .BE |
| .SH "DESCRIPTION" |
| .PP |
| The \fBtdbc::odbc\fR 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. |
| .PP |
| Connection to an ODBC database is established by invoking |
| \fBtdbc::odbc::connection create\fR, passing it the name to be used |
| as a connection handle, followed by a standard ODBC |
| connection string. As an alternative, \fBtdbc::odbc::connection new\fR |
| may be used to create |
| a database connection with an automatically assigned name. The return value |
| from \fBtdbc::odbc::connection new\fR is the name that was chosen for the |
| connection handle. |
| .PP |
| The connection string will include at least a |
| \fBDRIVER\fR or \fBDSN\fR keyword, and may include others that are defined by a |
| particular ODBC driver. (If the local ODBC system supports a graphical |
| user interface, the \fB-parent\fR option (see below) may allow calling |
| \fBtdbc::odbc::connection create\fR with an empty connection string.) |
| .PP |
| The side effect of \fBtdbc::odbc::connection create\fR is to create a |
| new database connection.. See \fBtdbc::connection(n)\fR for the |
| details of how to use the connection to manipulate a database. |
| .PP |
| In addition to a standard TDBC interface, \fBtdbc::odbc\fR supports |
| three additional ccommands. The first of these, |
| \fBtdbc::odbc::datasources\fR, which returns a Tcl |
| list enumerating the named data sources available to the program (for |
| connection with the \fBDSN\fR keyword in the connection string). |
| The result of \fBtdbc::odbc::datasources\fR may be constrained to only |
| system data sources or only user data sources by including the |
| \fB-system\fR or \fB-user\fR options, respectively. |
| .PP |
| The \fBtdbc::odbc::drivers\fR command returns a dictionary whose keys |
| are the names of drivers available for the \fBDRIVER\fR keyword in the |
| connection string, and whose values are descriptions of the drivers. |
| .PP |
| The \fBtdbc::odbc::datasource\fR command allows configuration of named |
| data sources on those systems that support the ODBC Installer |
| application programming interface. It accepts a \fIcommand\fR, which |
| specifies the operation to be performed, the name of a \fIdriver\fR |
| for the database in question, and a set of keyword-value pairs that |
| are interpreted by the given driver. The \fIcommand\fR must be one of |
| the following: |
| .IP \fBadd\fR |
| Adds a user data source. The keyword-value pairs must include |
| at least a \fBDSN\fR option naming the data source |
| .IP \fBadd_system\fR |
| Adds a system data source. The keyword-value pairs must include |
| at least a \fBDSN\fR option naming the data source |
| .IP \fBconfigure\fR |
| Configures a user data source. The keyword-value pairs will usually |
| include a \fBDSN\fR option naming the data source. Some drivers will |
| support other options, such as the \fBCREATE_DB\fR option to the |
| Microsoft Access driver on Windows. |
| .IP \fBconfigure_system\fR |
| Configures a system data source. |
| .IP \fBremove\fR |
| Removes a user data source. The keyword-value pairs must include a |
| \fBDSN\fR option specifying the data source to remove. |
| .IP \fBremove_system\fR |
| Removes a system data source. The keyword-value pairs must include a |
| \fBDSN\fR option specifying the data source to remove. |
| .SH "CONNECTION OPTIONS" |
| .PP |
| The \fBtdbc::odbc::connection create\fR object command supports the |
| \fB-encoding\fR, \fB-isolation\fR, \fB-readonly\fR and \fB-timeout\fR |
| options common to all TDBC drivers. The \fB-encoding\fR option will |
| succeed only if the requested encoding is the same as the system |
| encoding; \fBtdbc::odbc\fR does not attempt to specify alternative |
| encodings to an ODBC driver. (Some drivers accept encoding |
| specifications in the connection string.) |
| .PP |
| In addition, if Tk is present in the requesting interpreter, |
| and the local system's ODBC driver manager supports a graphical user |
| interface, the \fBtdbc::odbc::connection create\fR object command |
| supports a \fB-parent\fR 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. |
| .SH EXAMPLES |
| .PP |
| 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. |
| .PP |
| .CS |
| tdbc::odbc::connection create db \\ |
| "DSN={PAYROLL};UID={aladdin};PWD={Sesame}" |
| .CE |
| Connects to a named data source "PAYROLL", providing "aladdin" as a |
| user name and "Sesame" as a password. Uses \fBdb\fR as the name of the |
| connection. |
| .PP |
| .CS |
| 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 $connString |
| .CE |
| Opens a connection to a Microsoft Access database file whose |
| name is in \fI$fileName\fR. The database is opened in read-only |
| mode. The resulting connection is called "db2". |
| .PP |
| .CS |
| tdbc::odbc::connection create db3 \\ |
| "DRIVER=SQLite3;DATABASE=$fileName" |
| .CE |
| Opens a connection to a SQLite3 database whose name is in "$fileName". |
| .PP |
| .CS |
| tdbc::odbc::datasource add \\ |
| {Microsoft Access Driver (*.mdb)} \\ |
| DSN=MyTestDatabase \\ |
| DBQ=[file native [file normalize $fileName]] |
| .CE |
| Creates a new user data source with the name, "MyTestDatabase" bound |
| to a Microsoft Access file whose path name is in "$fileName". No |
| connection is made to the data source until the program calls |
| \fBtdbc::odbc::connection create\fR. |
| .PP |
| .CS |
| tdbc::odbc::datasource configure \\ |
| {Microsoft Access Driver (*.mdb)} \\ |
| CREATE_DB=[file native [file normalize $fileName]] \\ |
| General |
| .CE |
| Creates a new, empty Microsoft Access database in the file identified |
| by "$fileName". No connection is made to the database until the |
| program calls \fBtdbc::odbc::connection create\fR. |
| .SH "ADDITIONAL CONNECTION METHODS" |
| In addition to the usual methods on the tdbc::connection(n) object, |
| connections to an ODBC database support one additional method: |
| .IP \fI$connection\fR \fBevaldirect\fR \fIsqlStatement\fR |
| This method takes the given driver-native SQL code \fIsqlStatement\fR and |
| evaluates it without preparing it. The statement is not tokenized and must |
| not contain variable substitutions. Evaluating the \fIsqlStatement\fR |
| produces a result set of zero or more rows. The result of the command is a |
| list of dictionaries, with one list element per row in the result set (in |
| a similar format to the list returned by \fI$connection allrows -as dicts\fR). |
| \fIThis command is not recommended\fR for anything where the usual |
| \fIprepare\fR or \fIpreparecall\fR 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 \fBCREATE |
| DATABASE\fR or \fBCREATE PROCEDURE\fR), or that contain characters that |
| are reserved by the tokenizer, can be executed. |
| .SH "SEE ALSO" |
| tdbc(n), tdbc::connection(n), tdbc::resultset(n), tdbc::statement(n) |
| .SH "KEYWORDS" |
| TDBC, SQL, ODBC, database, connectivity, connection |
| .SH "COPYRIGHT" |
| Copyright (c) 2008 by Kevin B. Kenny. |
| .\" Local Variables: |
| .\" mode: nroff |
| .\" End: |
| .\" |
| |
