wxWidgets/include/wx/db.h

///////////////////////////////////////////////////////////////////////////////
// Name:        db.h
// Purpose:     Header file wxDB class.  The wxDB class represents a connection
//              to an ODBC data source.  The wxDB class allows operations on the data
//              source such as opening and closing the data source.
// Author:      Doug Card
// Modified by: George Tasker
// Mods:        Dec, 1998:
//                -Added support for SQL statement logging and database cataloging
//                     April, 1999
//                -Added QUERY_ONLY mode support to reduce default number of cursors
//                -Added additional SQL logging code
//                -Added DEBUG-ONLY tracking of Ctable objects to detect orphaned DB connections
//                -Set ODBC option to only read committed writes to the DB so all
//                     databases operate the same in that respect
//
// Created:     9.96
// RCS-ID:      $Id$
// Copyright:   (c) 1996 Remstar International, Inc.
// Licence:     wxWindows licence, plus:
// Notice:      This class library and its intellectual design are free of charge for use,
//              modification, enhancement, debugging under the following conditions:
//              1) These classes may only be used as part of the implementation of a
//                 wxWindows-based application
//              2) All enhancements and bug fixes are to be submitted back to the wxWindows
//                 user groups free of all charges for use with the wxWindows library.
//              3) These classes may not be distributed as part of any other class library,
//                 DLL, text (written or electronic), other than a complete distribution of
//                 the wxWindows GUI development toolkit.
//
///////////////////////////////////////////////////////////////////////////////

/*
// SYNOPSIS START
// SYNOPSIS STOP
*/

#ifndef DB_DOT_H
#define DB_DOT_H

// Use this line for wxWindows v1.x
//#include "wx_ver.h"
// Use this line for wxWindows v2.x
#include "wx/version.h"

#if wxMAJOR_VERSION == 2
    #ifdef __GNUG__
    #pragma interface "db.h"
    #endif
#endif

#include "wx/setup.h"

#if wxMAJOR_VERSION == 2
    extern "C" {
    #include "wx/isql.h"
    #include "wx/isqlext.h"
    }
#else  // version == 1
    extern "C" {
    #include "iodbc.h"
    #include "isqlext.h"
    }
#endif

typedef float SFLOAT; 
typedef double SDOUBLE; 
typedef unsigned int UINT;
#define ULONG UDWORD

#ifndef wxODBC_FWD_ONLY_CURSORS
#define wxODBC_FWD_ONLY_CURSORS 1
#endif

enum enumDummy {enumDum1};

#define SQL_C_BOOLEAN(datatype) (sizeof(datatype) == 1 ? SQL_C_UTINYINT : (sizeof(datatype) == 2 ? SQL_C_USHORT : SQL_C_ULONG))
//    #define SQL_C_BOOLEAN (sizeof(Bool) == 2 ? SQL_C_USHORT : SQL_C_ULONG)

#define SQL_C_ENUM (sizeof(enumDummy) == 2 ? SQL_C_USHORT : SQL_C_ULONG)

#ifndef TRUE
#define TRUE 1
#endif

#ifndef FALSE
#define FALSE 0
#endif

const int DB_PATH_MAX                 = 254;

extern char const *SQL_LOG_FILENAME;
extern char const *SQL_CATALOG_FILENAME;


// Database Globals
const int DB_TYPE_NAME_LEN            = 40;
const int DB_MAX_STATEMENT_LEN        = 2048;
const int DB_MAX_WHERE_CLAUSE_LEN     = 1024;
const int DB_MAX_ERROR_MSG_LEN        = 512;
const int DB_MAX_ERROR_HISTORY        = 5;
const int DB_MAX_TABLE_NAME_LEN       = 128;
const int DB_MAX_COLUMN_NAME_LEN      = 128;

const int DB_DATA_TYPE_VARCHAR        = 1;
const int DB_DATA_TYPE_INTEGER        = 2;
const int DB_DATA_TYPE_FLOAT          = 3;
const int DB_DATA_TYPE_DATE           = 4;

const int DB_SELECT_KEYFIELDS         = 1;
const int DB_SELECT_WHERE             = 2;
const int DB_SELECT_MATCHING          = 3;
const int DB_SELECT_STATEMENT         = 4;

const int DB_UPD_KEYFIELDS            = 1;
const int DB_UPD_WHERE                = 2;

const int DB_DEL_KEYFIELDS            = 1;
const int DB_DEL_WHERE                = 2;
const int DB_DEL_MATCHING             = 3;

const int DB_WHERE_KEYFIELDS          = 1;
const int DB_WHERE_MATCHING           = 2;

const int DB_GRANT_SELECT             = 1;
const int DB_GRANT_INSERT             = 2;
const int DB_GRANT_UPDATE             = 4;
const int DB_GRANT_DELETE             = 8;
const int DB_GRANT_ALL                = DB_GRANT_SELECT | DB_GRANT_INSERT | DB_GRANT_UPDATE | DB_GRANT_DELETE;

// ODBC Error codes (derived from ODBC SqlState codes)
enum ODBC_ERRORS
{
    DB_FAILURE                        = 0,
    DB_SUCCESS                        = 1,
    DB_ERR_NOT_IN_USE,
    DB_ERR_GENERAL_WARNING,                            // SqlState = '01000'
    DB_ERR_DISCONNECT_ERROR,                           // SqlState = '01002'
    DB_ERR_DATA_TRUNCATED,                             // SqlState = '01004'
    DB_ERR_PRIV_NOT_REVOKED,                           // SqlState = '01006'
    DB_ERR_INVALID_CONN_STR_ATTR,                      // SqlState = '01S00'
    DB_ERR_ERROR_IN_ROW,                               // SqlState = '01S01'
    DB_ERR_OPTION_VALUE_CHANGED,                       // SqlState = '01S02'
    DB_ERR_NO_ROWS_UPD_OR_DEL,                         // SqlState = '01S03'
    DB_ERR_MULTI_ROWS_UPD_OR_DEL,                      // SqlState = '01S04'
    DB_ERR_WRONG_NO_OF_PARAMS,                         // SqlState = '07001'
    DB_ERR_DATA_TYPE_ATTR_VIOL,                        // SqlState = '07006'
    DB_ERR_UNABLE_TO_CONNECT,                          // SqlState = '08001'
    DB_ERR_CONNECTION_IN_USE,                          // SqlState = '08002'
    DB_ERR_CONNECTION_NOT_OPEN,                        // SqlState = '08003'
    DB_ERR_REJECTED_CONNECTION,                        // SqlState = '08004'
    DB_ERR_CONN_FAIL_IN_TRANS,                         // SqlState = '08007'
    DB_ERR_COMM_LINK_FAILURE,                          // SqlState = '08S01'
    DB_ERR_INSERT_VALUE_LIST_MISMATCH,                 // SqlState = '21S01'
    DB_ERR_DERIVED_TABLE_MISMATCH,                     // SqlState = '21S02'
    DB_ERR_STRING_RIGHT_TRUNC,                         // SqlState = '22001'
    DB_ERR_NUMERIC_VALUE_OUT_OF_RNG,                   // SqlState = '22003'
    DB_ERR_ERROR_IN_ASSIGNMENT,                        // SqlState = '22005'
    DB_ERR_DATETIME_FLD_OVERFLOW,                      // SqlState = '22008'
    DB_ERR_DIVIDE_BY_ZERO,                             // SqlState = '22012'
    DB_ERR_STR_DATA_LENGTH_MISMATCH,                   // SqlState = '22026'
    DB_ERR_INTEGRITY_CONSTRAINT_VIOL,                  // SqlState = '23000'
    DB_ERR_INVALID_CURSOR_STATE,                       // SqlState = '24000'
    DB_ERR_INVALID_TRANS_STATE,                        // SqlState = '25000'
    DB_ERR_INVALID_AUTH_SPEC,                          // SqlState = '28000'
    DB_ERR_INVALID_CURSOR_NAME,                        // SqlState = '34000'
    DB_ERR_SYNTAX_ERROR_OR_ACCESS_VIOL,                // SqlState = '37000'
    DB_ERR_DUPLICATE_CURSOR_NAME,                      // SqlState = '3C000'
    DB_ERR_SERIALIZATION_FAILURE,                      // SqlState = '40001'
    DB_ERR_SYNTAX_ERROR_OR_ACCESS_VIOL2,               // SqlState = '42000'
    DB_ERR_OPERATION_ABORTED,                          // SqlState = '70100'
    DB_ERR_UNSUPPORTED_FUNCTION,                       // SqlState = 'IM001'
    DB_ERR_NO_DATA_SOURCE,                             // SqlState = 'IM002'
    DB_ERR_DRIVER_LOAD_ERROR,                          // SqlState = 'IM003'
    DB_ERR_SQLALLOCENV_FAILED,                         // SqlState = 'IM004'
    DB_ERR_SQLALLOCCONNECT_FAILED,                     // SqlState = 'IM005'
    DB_ERR_SQLSETCONNECTOPTION_FAILED,                 // SqlState = 'IM006'
    DB_ERR_NO_DATA_SOURCE_DLG_PROHIB,                  // SqlState = 'IM007'
    DB_ERR_DIALOG_FAILED,                              // SqlState = 'IM008'
    DB_ERR_UNABLE_TO_LOAD_TRANSLATION_DLL,             // SqlState = 'IM009'
    DB_ERR_DATA_SOURCE_NAME_TOO_LONG,                  // SqlState = 'IM010'
    DB_ERR_DRIVER_NAME_TOO_LONG,                       // SqlState = 'IM011'
    DB_ERR_DRIVER_KEYWORD_SYNTAX_ERROR,                // SqlState = 'IM012'
    DB_ERR_TRACE_FILE_ERROR,                           // SqlState = 'IM013'
    DB_ERR_TABLE_OR_VIEW_ALREADY_EXISTS,               // SqlState = 'S0001'
    DB_ERR_TABLE_NOT_FOUND,                            // SqlState = 'S0002'
    DB_ERR_INDEX_ALREADY_EXISTS,                       // SqlState = 'S0011'
    DB_ERR_INDEX_NOT_FOUND,                            // SqlState = 'S0012'
    DB_ERR_COLUMN_ALREADY_EXISTS,                      // SqlState = 'S0021'
    DB_ERR_COLUMN_NOT_FOUND,                           // SqlState = 'S0022'
    DB_ERR_NO_DEFAULT_FOR_COLUMN,                      // SqlState = 'S0023'
    DB_ERR_GENERAL_ERROR,                              // SqlState = 'S1000'
    DB_ERR_MEMORY_ALLOCATION_FAILURE,                  // SqlState = 'S1001'
    DB_ERR_INVALID_COLUMN_NUMBER,                      // SqlState = 'S1002'
    DB_ERR_PROGRAM_TYPE_OUT_OF_RANGE,                  // SqlState = 'S1003'
    DB_ERR_SQL_DATA_TYPE_OUT_OF_RANGE,                 // SqlState = 'S1004'
    DB_ERR_OPERATION_CANCELLED,                        // SqlState = 'S1008'
    DB_ERR_INVALID_ARGUMENT_VALUE,                     // SqlState = 'S1009'
    DB_ERR_FUNCTION_SEQUENCE_ERROR,                    // SqlState = 'S1010'
    DB_ERR_OPERATION_INVALID_AT_THIS_TIME,             // SqlState = 'S1011'
    DB_ERR_INVALID_TRANS_OPERATION_CODE,               // SqlState = 'S1012'
    DB_ERR_NO_CURSOR_NAME_AVAIL,                       // SqlState = 'S1015'
    DB_ERR_INVALID_STR_OR_BUF_LEN,                     // SqlState = 'S1090'
    DB_ERR_DESCRIPTOR_TYPE_OUT_OF_RANGE,               // SqlState = 'S1091'
    DB_ERR_OPTION_TYPE_OUT_OF_RANGE,                   // SqlState = 'S1092'
    DB_ERR_INVALID_PARAM_NO,                           // SqlState = 'S1093'
    DB_ERR_INVALID_SCALE_VALUE,                        // SqlState = 'S1094'
    DB_ERR_FUNCTION_TYPE_OUT_OF_RANGE,                 // SqlState = 'S1095'
    DB_ERR_INF_TYPE_OUT_OF_RANGE,                      // SqlState = 'S1096'
    DB_ERR_COLUMN_TYPE_OUT_OF_RANGE,                   // SqlState = 'S1097'
    DB_ERR_SCOPE_TYPE_OUT_OF_RANGE,                    // SqlState = 'S1098'
    DB_ERR_NULLABLE_TYPE_OUT_OF_RANGE,                 // SqlState = 'S1099'
    DB_ERR_UNIQUENESS_OPTION_TYPE_OUT_OF_RANGE,        // SqlState = 'S1100'
    DB_ERR_ACCURACY_OPTION_TYPE_OUT_OF_RANGE,          // SqlState = 'S1101'
    DB_ERR_DIRECTION_OPTION_OUT_OF_RANGE,              // SqlState = 'S1103'
    DB_ERR_INVALID_PRECISION_VALUE,                    // SqlState = 'S1104'
    DB_ERR_INVALID_PARAM_TYPE,                         // SqlState = 'S1105'
    DB_ERR_FETCH_TYPE_OUT_OF_RANGE,                    // SqlState = 'S1106'
    DB_ERR_ROW_VALUE_OUT_OF_RANGE,                     // SqlState = 'S1107'
    DB_ERR_CONCURRENCY_OPTION_OUT_OF_RANGE,            // SqlState = 'S1108'
    DB_ERR_INVALID_CURSOR_POSITION,                    // SqlState = 'S1109'
    DB_ERR_INVALID_DRIVER_COMPLETION,                  // SqlState = 'S1110'
    DB_ERR_INVALID_BOOKMARK_VALUE,                     // SqlState = 'S1111'
    DB_ERR_DRIVER_NOT_CAPABLE,                         // SqlState = 'S1C00'
    DB_ERR_TIMEOUT_EXPIRED                             // SqlState = 'S1T00'
};


struct DbStuff
{
    HENV Henv;
    char Dsn[SQL_MAX_DSN_LENGTH+1];                    // Data Source Name
    char Uid[20+1];                                    // User ID
    char AuthStr[20+1];                                // Authorization string (password)

    char description[SQL_MAX_DSN_LENGTH+1];            // Not sure what the max length is
    char fileType[SQL_MAX_DSN_LENGTH+1];               // Not sure what the max length is

    // Optionals needed for some databases like dBase
    char defaultDir[DB_PATH_MAX];                      // Directory that db file resides in
};


typedef struct
{
    char    TypeName[DB_TYPE_NAME_LEN];
    int     FsqlType;
    long    Precision;
    short   CaseSensitive;
//    short MinimumScale;
    short   MaximumScale;
} SqlTypeInfo;


class WXDLLEXPORT wxColFor
{
public:
    wxString       s_Field;             // Formated String for Output
    wxString       s_Format[7];         // Formated Objects - TIMESTAMP has the biggest (7)
    wxString       s_Menge[7];          // Formated Objects - amount of things that can be formatted
    int            i_Menge[7];          // Formated Objects - TT MM YYYY HH MM SS m
    int            i_Nation;            // 0 = timestamp , 1=EU, 2=UK, 3=International, 4=US
    int            i_dbDataType;        // conversion of the 'sqlDataType' to the generic data type used by these classes
    SWORD          i_sqlDataType;

    wxColFor();
    ~wxColFor();
  
    int            Format(int Nation, int dbDataType, SWORD sqlDataType, short columnSize, short decimalDigits);
};


class WXDLLEXPORT wxColInf
{
public:
    char         catalog[128+1];
    char         schema[128+1];
    char         tableName[DB_MAX_TABLE_NAME_LEN+1];
    char         colName[DB_MAX_COLUMN_NAME_LEN+1];
    SWORD        sqlDataType;
    char         typeName[128+1];
    SWORD        columnSize;
    SWORD        bufferLength;
    short        decimalDigits;
    short        numPrecRadix;
    short        nullable;
    char         remarks[254+1];
    int          dbDataType;  // conversion of the 'sqlDataType' to the generic data type used by these classes
 // mj10777.19991224 : new
    int          PkCol;       // Primary key column       0=No; 1= First Key, 2 = Second Key etc.
    char         PkTableName[DB_MAX_TABLE_NAME_LEN+1]; // Tables that use this PKey as a FKey
    int          FkCol;       // Foreign key column       0=No; 1= First Key, 2 = Second Key etc.
    char         FkTableName[DB_MAX_TABLE_NAME_LEN+1]; // Foreign key table name
    wxColFor    *pColFor;                              // How should this columns be formatted
};


class WXDLLEXPORT wxTableInf        // Description of a Table
{
public:
    char      tableName[DB_MAX_TABLE_NAME_LEN+1];
    char      tableType[254+1];           // "TABLE" or "SYSTEM TABLE" etc.
    char      tableRemarks[254+1];
    int       numCols;                    // How many Columns does this Table have: GetColumnCount(..);
    wxColInf *pColInf;                    // pColInf = NULL ; User can later call GetColumns(..);
};


class WXDLLEXPORT wxDbInf     // Description of a Database
{
public:
    char        catalog[128+1];
    char        schema[128+1];
    int         numTables;           // How many tables does this database have
    wxTableInf *pTableInf;           // pTableInf = new wxTableInf[numTables];
};


enum sqlLog
{
    sqlLogOFF,
    sqlLogON
};


// These are the databases currently tested and working with these classes
// See the comments in wxDB::Dbms() for exceptions/issues with
// each of these database engines
enum dbms
{
    dbmsUNIDENTIFIED,
    dbmsORACLE,
    dbmsSYBASE_ASA,        // Adaptive Server Anywhere
    dbmsSYBASE_ASE,        // Adaptive Server Enterprise
    dbmsMS_SQL_SERVER,
    dbmsMY_SQL,
    dbmsPOSTGRES,
    dbmsACCESS,
    dbmsDBASE,
    dbmsINFORMIX
};


typedef enum dbms DBMS;


// The wxDB::errorList is copied to this variable when the wxDB object
// is closed.  This way, the error list is still available after the
// database object is closed.  This is necessary if the database 
// connection fails so the calling application can show the operator
// why the connection failed.  Note: as each wxDB object is closed, it
// will overwrite the errors of the previously destroyed wxDB object in 
// this variable.
extern char DBerrorList[DB_MAX_ERROR_HISTORY][DB_MAX_ERROR_MSG_LEN];


// Backward compability for Remstar classes.  This
// will eventually go away, so the wxColXxxx classes
// should be used
typedef wxColInf CcolInf;


class WXDLLEXPORT wxDB
{
private:

    // Private data
    bool             dbIsOpen;
    char            *dsn;             // Data source name
    char            *uid;             // User ID
    char            *authStr;         // Authorization string (password)
    FILE            *fpSqlLog;        // Sql Log file pointer
    enum sqlLog      sqlLogState;     // On or Off
    bool             fwdOnlyCursors;

    // Private member functions
    bool             getDbInfo(void);
    bool             getDataTypeInfo(SWORD fSqlType, SqlTypeInfo &structSQLTypeInfo);
    bool             setConnectionOptions(void);
    void             logError(const char *errMsg, const char *SQLState);

public:
    // The following structure contains database information gathered from the
    // datasource when the datasource is first opened.
    struct
    {
        char   dbmsName[40];                             // Name of the dbms product
        char   dbmsVer[64];                              // Version # of the dbms product
        char   driverName[40];                           // Driver name
        char   odbcVer[60];                              // ODBC version of the driver
        char   drvMgrOdbcVer[60];                        // ODBC version of the driver manager
        char   driverVer[60];                            // Driver version
        char   serverName[80];                           // Server Name, typically a connect string
        char   databaseName[128];                        // Database filename
        char   outerJoins[2];                            // Indicates whether the data source supports outer joins
        char   procedureSupport[2];                      // Indicates whether the data source supports stored procedures
        UWORD  maxConnections;                           // Maximum # of connections the data source supports
        UWORD  maxStmts;                                 // Maximum # of HSTMTs per HDBC
        UWORD  apiConfLvl;                               // ODBC API conformance level
        UWORD  cliConfLvl;                               // Indicates whether the data source is SAG compliant
        UWORD  sqlConfLvl;                               // SQL conformance level
        UWORD  cursorCommitBehavior;                     // Indicates how cursors are affected by a db commit
        UWORD  cursorRollbackBehavior;                   // Indicates how cursors are affected by a db rollback
        UWORD  supportNotNullClause;                     // Indicates if data source supports NOT NULL clause
        char   supportIEF[2];                            // Integrity Enhancement Facility (Referential Integrity)
        UDWORD txnIsolation;                             // Default transaction isolation level supported by the driver
        UDWORD txnIsolationOptions;                      // Transaction isolation level options available
        UDWORD fetchDirections;                          // Fetch directions supported
        UDWORD lockTypes;                                // Lock types supported in SQLSetPos
        UDWORD posOperations;                            // Position operations supported in SQLSetPos
        UDWORD posStmts;                                 // Position statements supported
        UDWORD scrollConcurrency;                        // Concurrency control options supported for scrollable cursors
        UDWORD scrollOptions;                            // Scroll Options supported for scrollable cursors
        UDWORD staticSensitivity;                        // Indicates if additions, deletions and updates can be detected
        UWORD  txnCapable;                               // Indicates if the data source supports transactions
        UDWORD loginTimeout;                             // Number seconds to wait for a login request
    } dbInf;

    // ODBC handles
    HENV  henv;        // ODBC Environment handle
    HDBC  hdbc;        // ODBC DB Connection handle
    HSTMT hstmt;       // ODBC Statement handle

    // ODBC Error Inf.
    char   sqlState[20];
    SDWORD nativeError;
    char   errorMsg[SQL_MAX_MESSAGE_LENGTH];
    SWORD  cbErrorMsg;
    char   errorList[DB_MAX_ERROR_HISTORY][DB_MAX_ERROR_MSG_LEN];
    int    DB_STATUS;

    //Error reporting mode
    bool silent;

    // Number of Ctable objects connected to this db object
    unsigned int nTables;

    // Inf. about logical data types VARCHAR, INTEGER, FLOAT and DATE.
    // This inf. is obtained from the ODBC driver by use of the
    // SQLGetTypeInfo() function.  The key piece of inf. is the
    // type name the data source uses for each logical data type.
    // e.g. VARCHAR; Oracle calls it VARCHAR2.
    SqlTypeInfo typeInfVarchar, typeInfInteger, typeInfFloat, typeInfDate;
    
    // Public member functions
    wxDB(HENV &aHenv, bool FwdOnlyCursors=(bool)TRUE);
    bool         Open(char *Dsn, char *Uid, char *AuthStr);  // Data Source Name, User ID, Password
    void         Close(void);
    bool         CommitTrans(void);
    bool         RollbackTrans(void);
    bool         DispAllErrors(HENV aHenv, HDBC aHdbc = SQL_NULL_HDBC, HSTMT aHstmt = SQL_NULL_HSTMT);
    bool         GetNextError(HENV aHenv, HDBC aHdbc = SQL_NULL_HDBC, HSTMT aHstmt = SQL_NULL_HSTMT);
    void         DispNextError(void);
    bool         CreateView(const char *viewName, const char *colList, const char *pSqlStmt, bool attemptDrop=TRUE);
    bool         DropView(const char *viewName);
    bool         ExecSql(const char *pSqlStmt);
    bool         GetNext(void);
    bool         GetData(UWORD colNo, SWORD cType, PTR pData, SDWORD maxLen, SDWORD FAR *cbReturned);
    bool         Grant(int privileges, const char *tableName, const char *userList = "PUBLIC");
    int          TranslateSqlState(const char *SQLState);
    wxDbInf     *GetCatalog(char *userID);
    bool         Catalog(const char *userID=NULL, const char *fileName = SQL_CATALOG_FILENAME);
    int          GetKeyFields(char *tableName, wxColInf* colInf,int nocols);
    wxColInf    *GetColumns(char *tableName[], const char *userID=NULL);
    wxColInf    *GetColumns(char *tableName, int *numCols, const char *userID=NULL);
    int          GetColumnCount(char *tableName, const char *userID=NULL);
    char        *GetDatabaseName(void) {return dbInf.dbmsName;}
    char        *GetDataSource(void)   {return dsn;}
    char        *GetUsername(void)     {return uid;}
    char        *GetPassword(void)     {return authStr;}
    bool         IsOpen(void)          {return dbIsOpen;}
    HENV         GetHENV(void)         {return henv;}
    HDBC         GetHDBC(void)         {return hdbc;}
    HSTMT        GetHSTMT(void)        {return hstmt;}
    bool         TableExists(const char *tableName, const char *userID=NULL, const char *path=NULL);  // Table name can refer to a table, view, alias or synonym
    void         LogError(const char *errMsg, const char *SQLState = 0) {logError(errMsg, SQLState);}
    bool         SqlLog(enum sqlLog state, const char *filename = SQL_LOG_FILENAME, bool append = FALSE);
    bool         WriteSqlLog(const char *logMsg);
    DBMS         Dbms(void);
    bool         FwdOnlyCursors(void) {return fwdOnlyCursors;}
};  // wxDB

// This structure forms a node in a linked list.  The linked list of "DbList" objects
// keeps track of allocated database connections.  This allows the application to
// open more than one database connection through ODBC for multiple transaction support
// or for multiple database support.

struct DbList
{
    DbList *PtrPrev;                      // Pointer to previous item in the list
    char    Dsn[SQL_MAX_DSN_LENGTH+1];    // Data Source Name
    wxDB   *PtrDb;                        // Pointer to the wxDB object
    bool    Free;                         // Is item free or in use?
    DbList *PtrNext;                      // Pointer to next item in the list
};


#ifdef __WXDEBUG__
#include "wx/object.h"
class CstructTablesInUse : public wxObject
{
    public:
        const char    *tableName;
        ULONG          tableID;
        class wxDB    *pDb;
};  // CstructTablesInUse
#endif

// The following routines allow a user to get new database connections, free them
// for other code segments to use, or close all of them when the application has
// completed.

wxDB  WXDLLEXPORT *GetDbConnection(DbStuff *pDbStuff, bool FwdOnlyCursors=(bool)wxODBC_FWD_ONLY_CURSORS);
bool  WXDLLEXPORT  FreeDbConnection(wxDB *pDb);
void  WXDLLEXPORT  CloseDbConnections(void);
int   WXDLLEXPORT  NumberDbConnectionsInUse(void);


// This function sets the sql log state for all open wxDB objects
bool SqlLog(enum sqlLog state, const char *filename = SQL_LOG_FILENAME);


// This routine allows you to query a driver manager
// for a list of available datasources.  Call this routine
// the first time using SQL_FETCH_FIRST.  Continue to call it
// using SQL_FETCH_NEXT until you've exhausted the list.
bool WXDLLEXPORT GetDataSource(HENV henv, char *Dsn, SWORD DsnMax, char *DsDesc, SWORD DsDescMax,
                               UWORD direction = SQL_FETCH_NEXT);

#endif