Tribblix: manual page: Tdbc

Tdbc_Init(3) Tcl Database Connectivity Tdbc_Init(3)

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NAME

Tdbc_Init, Tdbc_MapSqlState, Tdbc_TokenizeSql - C procedures to
facilitate 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
containing a 'SQL state' from a
database error.

const char *sqlcode (in) Pointer to a character string
containing a SQL statement.
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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 information.

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 tokenizes the SQL statements, and returns a pointer to a Tcl_Obj
that contains 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
(distinguishing them from similar strings appearing inside
quotes or comments) and statement delimiters.

KEYWORDS

TDBC, SQL, database, tokenize