Informix-ESQL/C Programmer's Manual

Informix-ESQL/C Programmer's Manual
Chapter 2: INFORMIX-ESQL/C Data Types

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Data-Type Alignment Library Functions

The following ESQL/C library functions provide machine-independent size and alignment information for different data types and help you work with null database values.


Function Name	Description
risnull()	Checks whether a C variable is null
rsetnull()	Sets a C variable to null
rtypalign()	Aligns data on proper type boundaries
rtypmsize()	Gives byte size of `SQL` data types
rtypname()	Returns the name of a specified `SQL` data type
rtypwidth()	Returns minimum number of characters that a character data type needs to avoid truncation

When you compile your ESQL/C program with the esql command, esql calls on the linker to link these functions to your program. The following pages describe these functions.

risnull()

The risnull() function checks whether a C or an ESQL/C variable contains a null value.

Syntax

int risnull(type;  ptrvar)

		int  type;

		char  *ptrvar; 


type
is an integer that corresponds to the data type of a C or ESQL/C variable. This type can be any data type except var binary or an lvarchar pointer variable. For more information, see "Defined Constants for Data Types".

ptrvar  
is a pointer to the C or ESQL/C variable.

Usage

The risnull() function determines whether ESQL/C variables of all data types except var binary and lvarchar pointer variables contain a null value. To determine whether a var binary or lvarchar pointer host variable contains null, use the ifx_var_isnull() macro. For more information, see page 10-41.

Return Codes

1
The variable does contain a null value.

0
The variable does not contain a null value.

Example

This sample program is in the risnull.ec file in the demo directory.

/*

   *  risnull.ec  *



   This  program  checks  the  paid_date  column  of  the  orders  table for  NULL

   to  determine  whether  an  order  has  been  paid.

*/



#include  <stdio.h>



EXEC  SQL  include  sqltypes;



#define WARNNOTIFY          1

#define NOWARNNOTIFY    0


main()

{

    char  ans;

    long  ret,  exp_chk();



    EXEC  SQL  BEGIN  DECLARE  SECTION;

        long  order_num,  order_date,  ship_date,  paid_date;

    EXEC  SQL  END  DECLARE  SECTION;



    printf("RISNULL Sample ESQL Program running.\n\n");

    EXEC  SQL  connect  to  'stores7';        /*  open  stores7  database*/

    exp_chk("CONNECT  TO  stores7", NOWARNNOTIFY)



    EXEC  SQL  declare  c  cursor  for

        select  order_num,  order_date,  ship_date,  paid_date  from  orders;

    EXEC  SQL  open  c;

    if(exp_chk("OPEN  c", WARNNOTIFY) == 1)  /* Found warnings */

		exit(1);

    printf("\n  Order#\tPaid?\n");        /*  print  column  hdgs  */

    while(1)

		{

		EXEC  SQL  fetch  c  into  :order_num,  :order_date,  :ship_date,  :paid_date;

		if  ((ret  =  exp_chk("FETCH c"))  ==  100)	/*  if  end  of  rows  */

			break;			/*  terminate  loop  */

		if(ret  <  0)

			exit(1);

		printf("%5d\t",  order_num);

		if  (risnull(CDATETYPE,  (char  *)&paid_date))  /*  is  price  NULL  ?  */

			printf("NO\n");

		else

			printf("Yes\n");

		}

	printf("\nRISNULL Sample Program over.\n\n");

}
/*

 *  The  exp_chk() file contains the exception handling functions to

 *  check the  SQLSTATE  status  variable  to  see if  an  error  has  occurred

 *  following  an  SQL  statement.  If  a warning or an  error  has

 *  occurred,  exp_chk()  executes  the  GET  DIAGNOSTICS  statement  and

 *  prints the  detail  for  each  exception  that  is  returned.

 */



EXEC SQL include exp_chk.ec

For a complete listing of the exp_chk() function, see "Guide to the exp_chk.ec File" or refer to the exp_chk.ec file for a listing of this exception-handling function.

Example Output

RISNULL Sample ESQL Program running.





Order#		Paid?

 1001		Yes

 1002		Yes

 1003		Yes

 1004		NO

 1005		Yes

 1006		NO

 1007		NO

 1008		Yes

 1009		Yes

 1010		Yes

 1011		Yes

 1012		NO

 1013		Yes

 1014		Yes

 1015		Yes

 1016		NO

 1017		NO

 1018		Yes

 1019		Yes

 1020		Yes

 1021		Yes

 1022		Yes

 1023		Yes



RISNULL Sample Program over.

rsetnull()

The rsetnull() function sets a C variable to a value that corresponds to a database null value.

Syntax

int rsetnull(type,  ptrvar)

		int  type;

		char  *ptrvar; 


type
is an integer that corresponds to the data type of a C or ESQL/C variable. This type can be any data type except var binary or an lvarchar pointer variable. For more information, see "Defined Constants for Data Types". 

ptrvar  
is a pointer to the C or ESQL/C variable.

Usage

The rsetnull() function sets to null ESQL/C variables of all data types except var binary and lvarchar pointer host variables. To set a var binary or lvarchar pointer host variable to null, use the ifx_var_setnull() macro. For more information, see page 10-46.

Example

This sample program is in the rsetnull.ec file in the demo directory.

/*

      *  rsetnull.ec  *



      This  program  fetches  rows  from  the  stock  table  for  a  chosen  manufacturer

      and  allows  the  user  to  set  the  unit_price  to  NULL.

*/



#include  <stdio.h>

#include  <ctype.h>

EXEC  SQL  include  decimal;

EXEC  SQL  include  sqltypes;



#define WARNNOTIFY      1

#define NOWARNNOTIFY    0



#define  LCASE(c)  (isupper(c)  ?  tolower(c)  :  (c))



char format[] = "($$,$$$,$$$.&&)";




main()

{

	char decdsply[20];

	char  ans;

	long  ret,  exp_chk();



	EXEC SQL BEGIN DECLARE SECTION;

		short stock_num;

		char description[16];

		dec_t unit_price;

		char manu_code[4];

	EXEC SQL END DECLARE SECTION;



    printf("RSETNULL Sample ESQL Program running.\n\n");

    EXEC  SQL  connect  to  'stores7';        /*  connect  to  stores7  */

    exp_chk("Connect  to stores7", NOWARNNOTIFY);



    printf("This  program  selects  all  rows  for  a  given  manufacturer\n");

    printf("from  the  stock  table  and  allows  you  to  set  the  unit_price\n");

    printf("to  NULL.\n");

    printf("\nTo  begin,  enter  a  manufacturer  code  -  for  example:  'HSK'\n");

    printf("\nEnter  Manufacturer  code:  ");        /*  prompt  for  mfr.  code  */

    gets(manu_code);				/*  get  mfr.  code  */

    EXEC  SQL  declare  upcurs  cursor  for  		/*  declare  cursor  */

		select  stock_num,  description,  unit_price  from  stock

		where  manu_code  =  :manu_code

		for  update  of  unit_price;

    rupshift(manu_code);        /*  Make  mfr  code  upper  case  */

    EXEC  SQL  open  upcurs;  /*  open  select  cursor  */

    if(exp_chk("Open  cursor", WARNNOTIFY) == 1)

		exit(1);



    /*

	 * Display  Column  Headings

     */

    printf("\nStock  #  \tDescription  \t\tUnit  Price");

    while(1)

		{

		/*  get  a  row  */

		EXEC  SQL  fetch  upcurs  into  :stock_num,  :description,  :unit_price;

		if  ((ret  =  exp_chk("fetch", WARNNOTIFY))  ==  100)	        /*  if  end  of  rows  */

			break;

		if(ret == 1)

			exit(1);

		if(risnull(CDECIMALTYPE,  (char  *)  &unit_price))    /*  unit_price  NULL?  */

			continue;				/*  skip  to  next  row  */

		rfmtdec(&unit_price,  format,  decdsply);  /*  format  unit_price  */

		/*  display  item  */

		printf("\n\t%d\t%15s\t%s",  stock_num,  description,  decdsply);

		ans  =  '  ';

		/*  Set  unit_price  to  NULL?  y(es)  or  n(o)  */

		while((ans  =  LCASE(ans))  !=  'y'  &&  ans  !=  'n')

			{

			printf("\n.  .  .  Set  unit_price  to  NULL  ?  (y/n)  ");

			scanf("%1s",  &ans);

			}

		if  (ans  ==  'y')                              /*  if  yes,  NULL  to  unit_price  */

			{

			rsetnull(CDECIMALTYPE,  (char  *)  &unit_price);

			EXEC  SQL  update  stock  set  unit_price  =  :unit_price

				where  current  of  upcurs;        /*  and  update  current  row  */

			if(exp_chk("UPDATE", WARNNOTIFY) == 1)

				exit(1);

			}

		}

	printf("\nRSETNULL Sample Program over.\n\n");

}



/*

 *  The  exp_chk() file contains the exception handling functions to

 *  check the  SQLSTATE  status  variable  to  see if  an  error  has  occurred

 *  following  an  SQL  statement.  If  a warning or an  error  has

 *  occurred,  exp_chk()  executes  the  GET  DIAGNOSTICS  statement  and

 *  prints the  detail  for  each  exception  that  is  returned.

 */



EXEC SQL include exp_chk.ec

For a complete listing of the exp_chk() function, see "Guide to the exp_chk.ec File" or refer to the exp_chk.ec file for a listing of this exception-handling function.

Example Output

RSETNULL Sample ESQL Program running.



This program selects all rows for a given manufacturer

from the stock table and allows you to set the unit_price

to NULL.



To begin, enter a manufacturer code - for example: 'HSK'



Enter Manufacturer code: HSK



Stock #         Description             Unit Price

      1          baseball gloves          $800.00 

 . . . Set unit_price to NULL ? (y/n) n



      3          baseball bat             $240.00 

. . . Set unit_price to NULL ? (y/n) y



      4          football                 $960.00 

. . . Set unit_price to NULL ? (y/n) n



      110        helmet                   $600.00 

. . . Set unit_price to NULL ? (y/n) y



RSETNULL Sample Program over.

rtypalign()

The rtypalign() function returns the position of the next proper boundary for a variable of the specified data type.

Syntax

int rtypalign(pos,  type)

		int  pos;

		int  type; 


pos
is the current position in a buffer. 

type  
is an integer that corresponds to the data type of a C or ESQL/C variable. This type can be any data type except var binary. For more information, see "Defined Constants for Data Types".

Usage

The rtypalign() and rtypmsize() functions are useful when you use an sqlda structure to dynamically fetch data into a buffer. On many hardware platforms, integer and other numeric data types must begin on a work boundary. The C language memory allocation routines allocate memory that is suitably aligned for any data type, including structures. However, these routines do not perform alignment for the constituent components of the structure. The programmer is responsible for performing that alignment with functions such as rtypalign() and rtypmsize(). These functions provide machine independence for storing column data.

After a DESCRIBE statement determines column information, ESQL/C stores the value of type in sqlda.sqlvar->sqltype.

You can see an application of the rtypalign() function in the unload.ec demonstration program.

Return Code

>0
The return value is the offset of the next proper boundary for a variable of type data type.

Example

This sample program is in the rtypalign.ec file in the demo directory.

/*

      *  rtypalign.ec  *



      The  following  program  prepares  a  select  on  all  columns  of  the  orders

      table  and  then  calculates  the  proper  alignment  for  each  column  in  a  buffer.

*/



#include  <decimal.h>



EXEC  SQL  include  sqltypes;



#define WARNNOTIFY      1

#define NOWARNNOTIFY    0



main()

{

    int  i,  pos;

    long  ret,  exp_chk();

    struct  sqlda  *sql_desc;

    struct  sqlvar_struct  *col;



    printf("RTYPALIGN Sample ESQL Program running.\n\n");



    EXEC  SQL  connect  to  'stores7';              /*  open  stores7  database  */

    exp_chk("Connect  to", NOWARNNOTIFY);



    EXEC  SQL  prepare  query_1  from  "select  *  from  orders";     /*  prepare  select  */

    if(exp_chk("Prepare", WARNNOTIFY) == 1)

		exit(1);



    EXEC  SQL  describe  query_1  into  sql_desc;      /*  initialize  sqlda  */

    if(exp_chk("Describe", WARNNOTIFY) == 1)

		exit(1);



    col  =  sql_desc->sqlvar;

    printf("\n\ttype\t\tlen\tnext\taligned\n");         /*  display  column  hdgs.  */

    printf("\t\t\t\tposn\tposn\n\n");

    /*

	 * For  each  column  in  the  orders  table

     */

    i  =  0;

    pos  =  0;

    while(i++  <  sql_desc->sqld)

		{

		/*  Modify  sqllen  if  SQL  type  is  DECIMAL  or  MONEY  */

		if(col->sqltype  ==  SQLDECIMAL  ||  col->sqltype  ==  SQLMONEY)

			{

			col->sqllen  =  sizeof(dec_t);

			}

		/*

		  *  display  name  of  SQL  type,  length  and  un-aligned  buffer  position

		  */
		printf("\t%s\t\t%d\t%d",  rtypname(col->sqltype),  col->sqllen,  pos);



		pos  =  rtypalign(pos,  col->sqltype);    	          /*  align  pos.  for  type  */

		printf("\t%d\n",  pos);



		pos  +=  col->sqllen;                                     /*  set  next  position  */

		++col;                                                 /*  bump  to  next  column  */

	}

	printf("\nRTYPALIGN Sample Program over.\n\n");

}



/*

 *  The  exp_chk() file contains the exception handling functions to

 *  check the  SQLSTATE  status  variable  to  see if  an  error  has  occurred

 *  following  an  SQL  statement.  If  a warning or an  error  has

 *  occurred,  exp_chk()  executes  the  GET  DIAGNOSTICS  statement  and

 *  prints the  detail  for  each  exception  that  is  returned.

 */



EXEC SQL include exp_chk.ec

For a complete listing of the exp_chk() function, see "Guide to the exp_chk.ec File" or refer to the exp_chk.ec file for a listing of this exception-handling function.

Example Output

RTYPALIGN Sample ESQL Program running. 


type
len
next

posn	
aligned

posn






serial
4
0
0

date
4
4
4

integer
4
8
8

char
40
12
12

char
1
52
52

char
10
53
53

date
4
63
64

decimal
22
68
68

money
22
90
90

date
4
112
112








RTYPALIGN Sample Program over.

rtypmsize()

The rtypmsize() function returns the number of bytes you must allocate in memory for the specified ESQL/C or SQL data type.

Syntax

int rtypmsize(sqltype,  sqllen)

		int  sqltype;

		int  sqllen; 


sqltype  
is the integer code of the ESQL/C or SQL data type. For more information, see "Defined Constants for Data Types".

sqllen
is the number of bytes in the data file for the specified data type.

Usage

The rtypalign() and rtypmsize() functions are useful when you use an sqlda structure to dynamically fetch data into a buffer. These functions provide machine independence for the column-data storage.

Informix provides the rtypmsize() function to use with the sqlda structure that a DESCRIBE statement initializes. After a DESCRIBE statement determines column information, the value of sqltype and sqllen components reside in the components of the same name in each sqlda.sqlvar structure.

When rtypmsize() determines sizes for character data, keep the following size information in mind:

For CCHARTYPE (char) and CSTRINGTYPE (string), ESQL/C adds one byte to the number of characters for the null terminator.
For CFIXCHARTYPE (fixchar), ESQL/C does not add a null terminator.

You can see an application of the rtypmsize() function in the unload.ec demonstration program.

Return Codes

0
The sqltype is not a valid SQL type.

>0
The return value is the number of bytes that the sqltype data type requires.

Example

This sample program is in the rtypmsize.ec file in the demo directory.

/*

      *  rtypmsize.ec  *



      This  program  prepares  a  select  statement  on  all  columns  of  the

      catalog  table.  Then  it  displays  the  data  type  of  each  column  and  

      the  number  of  bytes  needed  to  store  it  in  memory.

*/



#include  <stdio.h>



EXEC  SQL  include  sqltypes;



#define WARNNOTIFY      1

#define NOWARNNOTIFY    0



EXEC  SQL  BEGIN  DECLARE  SECTION;

    char  db_name[20];

EXEC  SQL  END  DECLARE  SECTION;



main(argc,  argv)

int  argc;

char  *argv[];

{

    int  i;

    char  db_stmnt[50];

    long  exp_chk();

    struct  sqlda  *sql_desc;

    struct  sqlvar_struct  *col;



    printf("RTYPMSIZE Sample ESQL Program running.\n\n");



    if  (argc  >  2)				/*  correct  no.  of  args?  */

		{

		printf("\nUsage:  %s  [database]\nIncorrect  no.  of  argument(s)\n",

			argv[0]);

		exit(1);

		}

	strcpy(db_name,  "stores7");

    if  (argc  ==  2)

		strcpy(db_name,  argv[1]);



	EXEC  SQL  connect  to  :db_name;

	sprintf(db_stmnt,  "CONNECT  TO  %s",  argv[1]);

	exp_chk(db_stmnt, NOWARNNOTIFY);



	printf("Connected to  '%s' database.",  db_name);



    EXEC  SQL  prepare  query_1  from  'select  *  from  catalog';  /*  prepare  select  */

    if(exp_chk("Prepare", WARNNOTIFY) == 1)

		exit(1);

    EXEC  SQL  describe  query_1  into  sql_desc;	  	        /*  setup  sqlda  */

    if(exp_chk("Describe", WARNNOTIFY) == 1)

		exit(1);

    printf("\n\tColumn                            Type        Size\n\n");	        /*  column  hdgs.  */

    /*

     *  For  each  column  in  the  catalog  table  display  the  column  name  and

     *  the  number  of  bytes  needed  to  store  the  column  in  memory.

     */

    for(i  =  0,  col  =  sql_desc->sqlvar;  i  <  sql_desc->sqld;  i++,  col++)

	printf("\t%-20s%-8s%3d\n",  col->sqlname,  rtypname(col->sqltype),

	    rtypmsize(col->sqltype,  col->sqllen));



    printf("\nRTYPMSIZE Sample Program over.\n\n");

}



/*

 *  The  exp_chk() file contains the exception handling functions to

 *  check the  SQLSTATE  status  variable  to  see if  an  error  has  occurred

 *  following  an  SQL  statement.  If  a warning or an  error  has

 *  occurred,  exp_chk()  executes  the  GET  DIAGNOSTICS  statement  and

 *  prints the  detail  for  each  exception  that  is  returned.

 */

EXEC SQL include exp_chk.ec

For a complete listing of the exp_chk() function, see "Guide to the exp_chk.ec File" or refer to the exp_chk.ec file for a listing of this exception-handling function.

Example Output

RTYPMSIZE Sample ESQL Program running.



Connected to stores7 database. 


Column
Type
Size





catalog_num
serial   
4

stock_num
smallint
2

manu_code
char
4

cat_descr
text
64

cat_picture
byte
64

cat_advert
varchar
256








RTYPMSIZE Sample Program over.

rtypname()

The rtypname() function returns a null-terminated string that contains the name of the specified SQL data type.

Syntax

char  *rtypname(sqltype)

	int  sqltype; 


sqltype  
is an integer code for one of the SQL data types. For more information, see "Defined Constants for Data Types".

The rtypname() function converts a constant for an Informix SQL data type (which sqltypes.h defines) to a character string.

Return Codes

The rtypname function returns a pointer to a string that contains the name of the data type specified sqltype. If sqltype is an invalid value, rtypname() returns a null string (" ")

Example

This sample program is in the rtypname.ec file in the demo directory.

/*

      *  rtypname.ec  *



      This  program  displays  the  name  and  the  data  type  of  each  column

      in  the  'orders'  table.

*/



#include  <stdio.h>



EXEC  SQL  include  sqltypes;



#define WARNNOTIFY      1

#define NOWARNNOTIFY    0



main(argc,  argv)

int  argc;

char  *argv[];

{

    int  i;

    long  err_chk();

    char  db_stmnt[50];

    char  *rtypname();

    struct  sqlda  *sql_desc;

    struct  sqlvar_struct  *col;



    EXEC  SQL  BEGIN  DECLARE  SECTION;

	char  db_name[20];

    EXEC  SQL  END  DECLARE  SECTION;



    printf("RTYPNAME Sample ESQL Program running.\n\n");



    if  (argc  >  2)				/*  correct  no.  of  args?  */

		{

		printf("\nUsage:  %s  [database]\nIncorrect  no.  of  argument(s)\n",

			argv[0]);

		exit(1);

		}

	strcpy(db_name,  "stores7");
	if  (argc  ==  2)

		strcpy(db_name,  argv[1]);



	EXEC  SQL  connect  to  :db_name;

	sprintf(db_stmnt,  "CONNECT  TO  %s",  argv[1]);

	exp_chk(db_stmnt, NOWARNNOTIFY);



	printf("Connected to  '%s' database.",  db_name);

    EXEC  SQL  prepare  query_1  from  'select  *  from  orders';    /*  prepare  select  */

    if(exp_chk("Prepare", WARNNOTIFY) == 1)

		exit(1);

    EXEC  SQL  describe  query_1  into  sql_desc;	        /*  initialize  sqlda  */

    if(exp_chk("Describe", WARNNOTIFY) == 1)

		exit(1);

    printf("\n\tColumn  Name        \t\tSQL  type\n\n");



    /*

     *  For  each  column  in  the  orders  table  display  the  column  name  and

     *  the  name  of  the  SQL  data  type

     */

    for  (i  =  0,  col  =  sql_desc->sqlvar;  i  <  sql_desc->sqld;  i++,  col++)

	printf("\t%-15s\t\t%s\n",  col->sqlname,  rtypname(col->sqltype));



    printf("\nRTYPNAME Sample Program over.\n\n");

}



/*

 *  The  exp_chk() file contains the exception handling functions to

 *  check the  SQLSTATE  status  variable  to  see if  an  error  has  occurred

 *  following  an  SQL  statement.  If  a warning or an  error  has

 *  occurred,  exp_chk()  executes  the  GET  DIAGNOSTICS  statement  and

 *  prints the  detail  for  each  exception  that  is  returned.

 */



EXEC SQL include exp_chk.ec

For a complete listing of the exp_chk() function, see "Guide to the exp_chk.ec File" or refer to the exp_chk.ec file for a listing of this exception-handling function.

Example Output

RTYPNAME Sample ESQL Program running.



Connected to stores7 database

	Column Name   		 		SQL type



	order_num    	  			serial

	order_date   	 	 		date

	customer_num 		  		integer

	ship_instruct  				char

	backlog        				char

	po_num         				char

	ship_date      				date

	ship_weight    				decimal

	ship_charge    				money

	paid_date     		 		date



RTYPNAME Sample Program over.

rtypwidth()

The rtypwidth() function returns the minimum number of characters that a character data type needs to avoid truncation when you convert a value with an SQL data type to a character data type.

Syntax

int rtypwidth(sqltype,  sqllen)

		int  sqltype;

		int  sqllen; 



sqltype  

is the integer code of the SQL data type. For more information, see "Defined Constants for Data Types".


sqllen

is the number of bytes in the data file for the specified SQL data type.

Usage

Informix provides the rtypwidth() function for use with the sqlda structure that a DESCRIBE statement initializes. The sqltype and sqllen components correspond to the components of the same name in each sqlda.sqlvar structure.

Return Codes

0
The sqltype is not a valid SQL data type.

> 0
The return value is the minimum number of characters that the sqltype data type requires.

Example

This sample program is in the rtypwidth.ec file in the demo directory.

/*

      *  rtypwidth.ec  *



      This  program  displays  the  name  of  each  column  in  the  'orders'  table  and

      the  number  of  characters  required  to  store  the  column  when  the    

      data  type  is  converted  to  characters.

*/



#include  <stdio.h>



#define WARNNOTIFY      1

#define NOWARNNOTIFY    0



main(argc,  argv)

int  argc;

char  *argv[];

{

    int  i,  numchars;



    long  exp_chk();

    char  db_stmnt[50];

    struct  sqlda  *sql_desc;

    struct  sqlvar_struct  *col;



    EXEC  SQL  BEGIN  DECLARE  SECTION;

	char  db_name[20];

    EXEC  SQL  END  DECLARE  SECTION;



    printf("RTYPWIDTH Sample ESQL Program running.\n\n");



    if  (argc  >  2)				/*  correct  no.  of  args?  */

		{

		printf("\nUsage:  %s  [database]\nIncorrect  no.  of  argument(s)\n",

		argv[0]);

		exit(1);

		}

	strcpy(db_name,  "stores7");

    if  (argc  ==  2)

		strcpy(db_name,  argv[1]);



	EXEC  SQL  connect  to  :db_name;

	sprintf(db_stmnt,  "CONNECT  TO  %s",  argv[1]);

	exp_chk(db_stmnt, NOWARNNOTIFY);



	printf("Connected to %s\n", db_name);



    EXEC  SQL  prepare  query_1  from  'select  *  from  orders';    /*  prepare  select  */

    if(exp_chk("Prepare", WARNNOTIFY) == 1)

		exit(1);

    EXEC  SQL  describe  query_1  into  sql_desc;	         /*  setup  sqlda  */

    if(exp_chk("Describe", WARNNOTIFY) == 1)

		exit(1);

    printf("\n\tColumn  Name        \t#  chars\n");



    /*

     *  For  each  column  in  orders  print  the  column  name  and  the  minimum

     *  number  of  characters  required  to  convert  the  SQL  type  to  a  character

     *  data  type

     */

    for  (i  =  0,  col  =  sql_desc->sqlvar;  i  <  sql_desc->sqld;  i++,  col++)

		{

		numchars  =  rtypwidth(col->sqltype,  col->sqllen);

		printf("\t%-15s\t%d\n",  col->sqlname,  numchars);

		}



    printf("\nRTYPWIDTH Sample Program over.\n\n");

}



/*

 *  The  exp_chk() file contains the exception handling functions to

 *  check the  SQLSTATE  status  variable  to  see if  an  error  has  occurred

 *  following  an  SQL  statement.  If  a warning or an  error  has

 *  occurred,  exp_chk()  executes  the  GET  DIAGNOSTICS  statement  and

 *  prints the  detail  for  each  exception  that  is  returned.

 */

EXEC SQL include exp_chk.ec

For a complete listing of the exp_chk() function, see "Guide to the exp_chk.ec File" or refer to the exp_chk.ec file for a listing of this exception-handling function.

Example Output

RTYPWIDTH Sample ESQL Program running.



Connected to stores7



	Column Name    				# chars

	order_num      				11

	order_date     				10

	customer_num   				11

	ship_instruct  				40

	backlog        				1

	po_num        			 	10

	ship_date     			 	10

	ship_weight    				10

	ship_charge    				9

	paid_date      				10



RTYPWIDTH Sample Program over.

Informix-ESQL/C Programmer's ManualChapter 2: INFORMIX-ESQL/C Data Types Home Contents Index Master Index New Book

Data-Type Alignment Library Functions

Usage

Return Codes 1 The variable does contain a null value. 0 The variable does not contain a null value.

Example

rsetnull()

Usage

rtypalign()

Usage

Return Code >0 The return value is the offset of the next proper boundary for a variable of type data type.

Example

rtypmsize()

Usage

Return Codes 0 The sqltype is not a valid SQL type. >0 The return value is the number of bytes that the sqltype data type requires.

Example

rtypname()

rtypwidth()

Usage

Return Codes 0 The sqltype is not a valid SQL data type. > 0 The return value is the minimum number of characters that the sqltype data type requires.

Example

Informix-ESQL/C Programmer's Manual
Chapter 2: INFORMIX-ESQL/C Data Types

Home Contents Index Master Index New Book

Return Codes

1
The variable does contain a null value.

0
The variable does not contain a null value.

Return Code

>0
The return value is the offset of the next proper boundary for a variable of type data type.

Return Codes

0
The sqltype is not a valid SQL type.

>0
The return value is the number of bytes that the sqltype data type requires.

Return Codes

0
The sqltype is not a valid SQL data type.

> 0
The return value is the minimum number of characters that the sqltype data type requires.