DOKK / manpages / debian 10 / tcl8.6-tdbc / Tdbc_Init.3.en
Tdbc_Init(3) Tcl Database Connectivity Tdbc_Init(3) 







Tdbc_Init, Tdbc_MapSqlState, Tdbc_TokenizeSql - C procedures to
    facilitate writing TDBC drivers








#include <tdbc.h>
int
Tdbc_Init(interp)
Tcl_Obj *
Tdbc_TokenizeSql(interp, sqlcode)
const char *
Tdbc_MapSqlState(state)









  
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.
    
    

    

  










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...".)








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.










tdbc(3tcl), tdbc::mapSqlState(3tcl), tdbc::tokenize(3tcl)








TDBC, SQL, database, tokenize








Copyright (c) 2009 by Kevin B. Kenny.







  

    8.6
    Tcl