n_settexisparam(), n_paramtx(), n_resetparamtx() - SQL interface

SYNOPSIS

int n_settexisparam(se, ipar, buf, len, ctype, sqltype)
SERVER  *se;
int     ipar;
void    *buf;
int     *len;
int     ctype;
int     sqltype;

int n_paramtx(se, tx, ipar, buf, len, ctype, sqltype)
SERVER  *se;
TX      *tx;
int     ipar;
void    *buf;
int     *len;
int     ctype;
int     sqltype;

int n_resetparamtx(se, tx)
SERVER	*se;
TX	*tx;

DESCRIPTION
These functions allow you to pass arbitrarily large or complex data into a SQL statement. Sometimes there is data that won't work in the confines of the simple C string that comprises an SQL statement. Large text fields or binary data for example.

Call n_settexisparam() to setup the parameter data before calling n_texis() or n_settx() to prepare the SQL statement. Call n_paramtx() to setup parameters after n_preptx() and before n_exectx(). If you have a statement you have already executed once, and you want to execute again with different data, which may have parameters unset which were previously unset you can call n_resetparamtx(). This is not neccessary if you will explicitly set all the parameters. Place a question mark (?) in the SQL statement where you would otherwise place the data.

These are the parameters:

SERVER *se

The open server connection.

TX *tx

The prepared SQL statement (n_paramtx() only).

int ipar

The number of the parameter, starting at 1.

void *buf

A pointer to the data to be transmitted.

int *len

A pointer to the length of the data. This can be (int *)NULL to use the default length, which assumes a '\0' terminated string for character data.

int ctype

The type of the data. For text use SQL_C_CHAR.

int sqltype

The type of the field being inserted into. For varchar use SQL_LONGVARCHAR.

EXAMPLE

SERVER *se;
TX     *tx;
char   *description;
char   *article;
int     len;

   ...
   description="a really large article";
   article=...
   len=...
   if(!n_settexisparam(se,1,article,&len, SQL_C_CHAR, SQL_LONGVARCHAR))
      puts("n_settexisparam failed");
   else
   if(!n_texis(se,"insert into docs values('%s',?);",description))
      puts("insert failed");
   ...

EXAMPLE

SERVER *se;
TX     *tx;
char   *description;
char   *article;
int     lend, lena;

   if(!n_preptx(se,tx,"insert into docs values(?,?);"))
      { puts("n_preptx Failed"); return(0); }
   ...
   description="a really large article";
   lend=strlen(description);
   article=...
   lena=strlen(article);
   if(!n_paramtx(se,tx,1,description,&lend,SQL_C_CHAR,SQL_LONGVARCHAR)||
      !n_paramtx(se,tx,2,article    ,&lena,SQL_C_CHAR,SQL_LONGVARCHAR));
      { puts("n_paramtx Failed"); return(0); }
   if(!n_exectx(se,tx))
      { puts("n_exectx Failed"); return(0); }
   ...