Tdbc_Init(3) Tcl Database Connectivity Tdbc_Init(3)______________________________________________________________________________NAME
Tdbc_Init, Tdbc_MapSqlState, Tdbc_TokenizeSql - C procedures to facili‐
tate writing TDBC drivers
SYNOPSIS
#include <tdbc.h>
int
Tdbc_Init(interp)
Tcl_Obj *
Tdbc_TokenizeSql(interp, sqlcode)
const char *
Tdbc_MapSqlState(state)ARGUMENTS
Tcl_Interp *interp (in/out) Pointer to a Tcl interpreter.
const char *state (in) Pointer to a character string con‐
taining a 'SQL state' from a data‐
base error.
const char *sqlcode (in) Pointer to a character string con‐
taining a SQL statement.
_________________________________________________________________DESCRIPTION
The TDBC library provides several C procedures that simplify writing a
TDBC driver. They include a procedure that tokenizes a SQL statement,
locating variables to be substituted, and a procedure that accepts a
SQL state and returns an error class for the interpreter error informa‐
tion.
Tdbc_Init must be invoked prior to any other TDBC call. It accepts a
pointer to a Tcl interpreter, and arranges to load the TDBC library. It
returns TCL_OK if the Tcl library was loaded successfully, and
TCL_ERROR otherwise. If TCL_ERROR is returned, the interpreter's result
contains the error message.
Tdbc_TokenizeSql accepts a pointer to a Tcl interpreter, and a pointer
to a character string containing one or more SQL statements. It tok‐
enizes the SQL statements, and returns a pointer to a Tcl_Obj that con‐
tains a list of the tokens that make up the statement. Concatenating
the tokens together will yield the original SQL code. The returned
Tcl_Obj has a reference count of zero. The caller is responsible for
managing the reference count as needed. See TOKENS below for a
description of what may be in the returned list of tokens.
Tdbc_MapSqlState accepts a pointer to a string, usually five characters
long, that is the 'SQL state' that resulted from a database error. It
returns a character string that is suitable for inclusion as the error
class when constructing the error code for an error in a TDBC driver.
(By convention, the error code is a list having at least four elements:
"TDBC errorClass sqlstate driverName details...".)
TOKENS
Each token returned from Tdbc_TokenizeSql may be one of the following:
[1] A bound variable, which begins with one of the characters ':',
'@', or '$'. The remainder of the string is the variable name
and will consist of alphanumeric characters and underscores.
(The leading character will be be non-numeric.)
[2] A semicolon that separates two SQL statements.
[3] Something else in a SQL statement. The tokenizer does not
attempt to parse SQL; it merely identifies bound variables (dis‐
tinguishing them from similar strings appearing inside quotes or
comments) and statement delimiters.
SEE ALSOtdbc(n), tdbc::mapSqlState(n), tdbc::tokenize(n)KEYWORDS
TDBC, SQL, database, tokenize
COPYRIGHT
Copyright (c) 2009 by Kevin B. Kenny.
Tcl 8.6 Tdbc_Init(3)
