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INFORMIX DRIVER FOR ABSTRACT DATA BASE CONNECTOR
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1. Informix ESQL/C info

 o Driver was developed using free Informix ESQL/C on Linux (7.24.UC5)

 o The file "informix/ix_dbc.esql.ec" must be processed with esql/c,
   before compilation. This may be done with `make informix'

 o Because the driver source is C++, actually it is ESQL/C hack.
   This include C++ like comments, sometimes `unsigned' keyword,
   C++ classes... etc.

2. Informix link libraies

Informix link libraies varring between diferent versions of ESQL/C
To get list for your system try:
	`esql -libs'

We recommend that you check this and then compare it with the file:
	`make/Makefile.dbc.ix'

3. Limitations: SIZE

Because ESQL/C works with fixed types actually my ESQL (7.24.UC5) uses 
sizeof(), we need to make some restrictions about field length. I deside that
following restrictions (marked by `a_dbc') are enought:

+---------------+--------------------+------+------------+
| Description   | Intenal C++ source | Len  | Limit from |
+---------------+--------------------+------+------------+
| database name | DB_BUFF_SIZE       |    30| Informix   |
| SQL len       | SQL_BUFF_SIZE      |  10KB| a_dbc      |
| field name len| FIELDNAME_BUFF_SIZE|    40| Informix   |
| max field len | FIELD_BUFF_SIZE    |  10KB| a_dbc (*)  |
+---------------+--------------------+------+------------+
                       (*) Informix SE record len is 32KB

Remark:
   Limitations may be changed with editing file "informix/ix_dbc.esql.ec"

4. Limitations: TRIM

A_DBC always will trim_right your fields!!!
Remark:
   Trimming right is removing all spaces from right side of a string:

void trim_right(char *s){
   for(size_t i = strlen(s) - 1 - 1; i > 0; i--)
      if (s[i] == ' ')
         s[i]='\0';
      else
         return;
} //trim_right

Remark:
   This limitation may be changed with editing file "informix/ix_dbc.esql.ec",
   but we do not recomend that you doing this, because Informix will made len
   to be equal to sizeof() field buffer FIELD_BUFF_SIZE (e.g. 10KB!!!:)

   Another way is to hack source and write some code for fixing field value
   sizes to their actual sizes (e.g. xx for `char(xx)'). Unfortunately this is 
   much complicated and less useful and sureless (is there word as this:).

const char *IxDBC::getFieldData(unsigned int no){
...
if (len + 1 < FIELD_BUFF_SIZE) //Do we need of this `if'?
   data[len + 1]='\0';
...
}

5. Limitations: BLOb's

The libary DO NOT recognize correct Informix BLOb types (SQLTEXT, SQLBYTES).
This is because small part of Informix ESQL/C file (BLOb's memory rediector) 
is not included in driver. (Do this for homework if you need it).

This is NOT a BIG problem since a_dbc not have any special support for BLOb's