sqllogictest

  if {$m>0} {
    set op [expr {rand()>0.5 ? "\n    OR " : "\n   AND "}]
    set w [lrange [scramble $wexpr] 1 $m]
    append sql "\n WHERE [join $w $op]"
  }
  incr n -1
  append sql "\n ORDER BY [join [scramble [lrange $sequence 0 $n]] ,]"
  # uncomment below to add LIMIT/OFFSET support.   MS SQL Server doesn't 
  # support this currently.
  #append sql "\n LIMIT [expr {int(rand()*5)+1}]"
  #if {rand()>0.5} {
  # append sql " OFFSET [expr {int(rand()*5)+1}]"

  #}
  puts "query [string range $type 0 $n] nosort"
  puts "$sql"
  puts ""
}

**
*******************************************************************************
** Here begins the implementation of the ODBC3 DbEngine object.
**
** This DbEngine expects an ODBC3 DSN named 'sqllogictest'
** and a database named 'slt' available through that DSN to exist.
** The DSN should be accessible to the current user.
** On connect, it will attempt to "DROP" all existing tables 
** from the database name 'slt' to reset it to a known status.
**
** The DSN name and DB name are controlled by the defines
** SLT_DSN and SLT_DB.
**
*/
#ifdef WIN32
#include <windows.h>
#endif
#define SQL_NOUNICODEMAP
#include <sql.h>
#include <sqlext.h>


#define SLT_DSN "sqllogictest"
#define SLT_DB  "slt"


/* 
** Forward prototypes.
*/
static int ODBC3Statement(
  void *pConn,                /* Connection created by xConnect */
  const char *zSql            /* SQL statement to evaluate */
);


/*
** Structure used to hold handles needed for ODBC3 connection.
*/
typedef struct ODBC3_Handles ODBC3_Handles;
struct ODBC3_Handles {
  SQLHENV env;

/*
** This routine is called to open a connection to a new, empty database.
** The zConnectStr argument is the value of the -connection command-line
** option.  This is intended to contain information on how to connect to
** the database engine.  The zConnectStr argument will be NULL if there
** is no -connection on the command-line.  

**
** An object that describes the newly opened and initialized database
** connection is returned by writing into *ppConn.
**
** This routine returns 0 on success and non-zero if there are any errors.
*/
static int ODBC3Connect(
  void *NotUsed,              /* Argument from DbEngine object.  Not used */
  const char *zConnectStr,    /* Connection string */
  void **ppConn               /* Write completed connection here */
){
  int rc = 0;
  SQLRETURN ret; /* ODBC API return status */
  ODBC3_Handles *pODBC3conn = NULL;
  char szSqlConnStr[512];

  /* Allocate a structure to hold all of our ODBC3 handles */
  pODBC3conn = (ODBC3_Handles *)malloc(sizeof(ODBC3_Handles));
  if( !pODBC3conn ){
    fprintf(stderr, "out of memory at %s:%d\n", __FILE__, __LINE__);
    return 1;
  }
  pODBC3conn->env = SQL_NULL_HENV;
  pODBC3conn->dbc = SQL_NULL_HDBC;

  /* Allocate an environment handle */
  SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &pODBC3conn->env);

static int ODBC3Query(
  void *pConn,                /* Connection created by xConnect */
  const char *zSql,           /* SQL statement to evaluate */
  const char *zType,          /* One character for each column of result */
  char ***pazResult,          /* RETURN:  Array of result values */
  int *pnResult               /* RETURN:  Number of result values */
){
  int rc = 0;
  SQLRETURN ret;              /* ODBC API return status */
  ODBC3_Handles *pODBC3conn = pConn;
  ODBC3_resAccum res;         /* query result accumulator */
  char zBuffer[512];          /* Buffer to render numbers */
  SQLSMALLINT columns;        /* number of columns in result-set */
  SQLHSTMT stmt = SQL_NULL_HSTMT;

  /* zero out accumulator structure */
  memset(&res, 0, sizeof(res));

  /* Allocate a statement handle */
  ret = SQLAllocHandle(SQL_HANDLE_STMT, pODBC3conn->dbc, &stmt);
  if( !SQL_SUCCEEDED(ret) && (ret != SQL_SUCCESS_WITH_INFO) ){
    ODBC3_perror("SQLAllocHandle", pODBC3conn->dbc, SQL_HANDLE_DBC);
    return 1;
  }

  ret = SQLExecDirect(stmt, (SQLCHAR *)zSql, SQL_NTS);
  if( !SQL_SUCCEEDED(ret) && (ret != SQL_SUCCESS_WITH_INFO) ){
    ODBC3_perror("SQLExecDirect", stmt, SQL_HANDLE_STMT);
    rc = 1;
  }

  if( !rc ){
    /* How many columns are there */
    ret = SQLNumResultCols(stmt, &columns);
    if( !SQL_SUCCEEDED(ret) && (ret != SQL_SUCCESS_WITH_INFO) ){
      ODBC3_perror("SQLNumResultCols", stmt, SQL_HANDLE_STMT);
      rc = 1;
    }
  }
  
  if( !rc ){
    /* Loop through the rows in the result-set */
    do {
      ret = SQLFetch(stmt);
      if( SQL_SUCCEEDED(ret) ){
        SQLUSMALLINT i;
        /* Loop through the columns */
        for(i = 1; i <= columns; i++){
          SQLINTEGER indicator;
          /* retrieve column data as a string */
          ret = SQLGetData(stmt, 
                           i, 
                           SQL_C_CHAR,
                           zBuffer, 
                           sizeof(zBuffer), 
                           &indicator);
          if( SQL_SUCCEEDED(ret) ){
            char *z;
            /* Handle null columns */
            if( indicator == SQL_NULL_DATA ){ 
              strcpy(zBuffer, "NULL");
            /* Handle empty columns */
            } else if( *zBuffer == '\0' ) {
              strcpy(zBuffer, "(empty)");
            }
            ODBC3_appendValue(&res, zBuffer);
            /* Convert non-printing and control characters to '@' */
            z = res.azValue[res.nUsed-1];
            while( *z ){
              if( *z<' ' || *z>'~' ){ *z = '@'; }
              z++;
            }
          }
        } /* end for i */
      }
    } while( SQL_SUCCEEDED(ret) );
  }
  
  if( stmt != SQL_NULL_HSTMT ){
    SQLFreeHandle(SQL_HANDLE_STMT, stmt);
  }

  *pazResult = res.azValue;
  *pnResult = res.nUsed;

  return rc;
}


/*
** This interface is called to free the memory that was returned
** by xQuery.
**

  void *pConn                 /* Connection created by xConnect */
){
  int rc = 0;
  SQLRETURN ret; /* ODBC API return status */
  ODBC3_Handles *pODBC3conn = pConn;
  
  if ( !pODBC3conn ){
    fprintf(stderr, "invalid ODBC3 connection object\n");
    return 1;
  }

  ret = SQLDisconnect(pODBC3conn->dbc);   /* disconnect from driver */
  if( !SQL_SUCCEEDED(ret) && (ret != SQL_SUCCESS_WITH_INFO) ){
    ODBC3_perror("SQLDisconnect", pODBC3conn->dbc, SQL_HANDLE_DBC);
    rc = 1;