Tdbc_Init, Tdbc_MapSqlState, Tdbc_TokenizeSql — C procedures to facilitate writing TDBC drivers
- Tdbc_Init, Tdbc_MapSqlState, Tdbc_TokenizeSql — C procedures to facilitate writing TDBC drivers
- SEE ALSO
const char *
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.
- 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.
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
Each token returned from Tdbc_TokenizeSql may be one of the
tdbc, tdbc::mapSqlState, tdbc::tokenize
TDBC, SQL, database, tokenize
Copyright (c) 2009 by Kevin B. Kenny.
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.)
A semicolon that separates two SQL statements.
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
Copyright © 2009 by Kevin B. Kenny.