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数据库技术在BREW中的应用 |
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时间: 2003-11-25 来自：sunwhite |
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3、关闭数据库
代码：
// IDATABASE_Release closes the open database files, and frees
//
any memory associated with the database.
if
(pIDatabase)
{
IDATABASE_Release (pIDatabase);
}
//
Release IDBMgr object. This step needs to be done
// only if no further
use of the IDBMgr object is needed.
if (pIDBMgr)
{
IDBMGR_Release
(pIDBMgr);
} |
4、创建一条记录
代码：
boolean CreateOneRecord(IDatabase * pIDatabase, AEEDBField * dbField,
int nNumfields)
{
IDBRecord * pIDBRecord = NULL;
//
IDATABASE_CreateRecord: creates a new database record with the fields
// specified by pDBFields.
if ((pIDBRecord = IDATABASE_CreateRecord
(pIDatabase, dbField, nNumfields)) != NULL)
{
// Successfully
created a database record.
// Release record
IDBRECORD_Release
(pIDBRecord);
return TRUE;
}
else
{
//Create DB
Record Failed
}
return
FALSE;
} |
dbField指向数据库记录域，nNumfields是域的个数。可以创建一个这样的记录：
代码：
{
AEEDBField dbField[3];
int nNumfields = 3;
const char
firstName [] = "John";
const char lastName [] = "Smith";
const char
address [] = "123 First Street, USA";
AEEDBFieldType
fieldType;
AEEDBFieldName fieldName;
// Data fill values used to
create a database record.
// The parameter dbField is a three item
array of type
// AEEDBField. Each array item corresponds to three
fields
// of the record.
dbField[0].fName =
AEEDBFIELD_FIRSTNAME;
dbField[0].fType =
AEEDB_FT_STRING;
dbField[0].pBuffer = (void
*)firstName;
dbField[0].wDataLen = STRLEN
(firstName);
dbField[1].fName =
AEEDBFIELD_LASTNAME;
dbField[1].fType =
AEEDB_FT_STRING;
dbField[1].pBuffer = (void
*)lastName;
dbField[1].wDataLen = STRLEN
(lastName);
dbField[2].fName =
AEEDBFIELD_ADDRESS;
dbField[2].fType =
AEEDB_FT_STRING;
dbField[2].pBuffer = (void
*)address;
dbField[2].wDataLen = STRLEN (address);
return
CreateOneRecord(pIDatabase, dbField,
3);
}
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5、获取记录个数
代码：
uint32 GetRecordCount(IDatabase * pIDatabase)
{
//
IDATABASE_GetRecordCount: returns the number of records in the
//
database specified. This gives the number of records in the
// database
prior to creating any records in the database.
return
IDATABASE_GetRecordCount
(pIDatabase);
} |
6、读取记录域
代码：
boolean GetRecordByID(IDatabase * pIDatabase, uint16
u16RecID)
{
IDBRecord * pIDBRec1 = NULL;
AEEDBFieldType
fType;
AEEDBFieldName fName;
uint16 fLen;
byte * data =
NULL;;
// This will reset the record Index to 0.
IDATABASE_Reset
(pIDatabase);
// IDATABASE_GetRecordByID: returns a pointer to the
record whose
// record ID is specified.
pIDBRec1 =
IDATABASE_GetRecordByID (pIDatabase, u16RecID);
// Get the raw data
of the field
for(;;)
{
// Get record 1 first field and display
it
fType = IDBRECORD_NextField (pIDBRec1, &fName,
&fLen);
data = IDBRECORD_GetField (pIDBRec1, &fName,
&fType, &fLen);
if (data !=
NULL)
{
switch(fName)
{
case
AEEDBFIELD_FIRSTNAME;
break;
case
AEEDBFIELD_LASTNAME;
break;
case
AEEDBFIELD_ADDRESS;
break;
default:
break;
}
}
else
{
break;
//break for
}
}
// Now remove record
1.
IDBRECORD_Release(pIDBRec1);
return TRUE;
}
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