$strTableName = $this->tablePrefix . sprintf('%02d', bcmod(sprintf('%u', crc32($intUid)), "100"));这句代码是什么意思

这句代码是将用户ID `$intUid` 的 CRC32 值取模 100，然后附加到 `$this->tablePrefix` 后面作为表名。其中，`$this->tablePrefix` 是表前缀，`bcmod` 是 PHP 的一个函数，用于对两个数进行取模运算，返回余数。`sprintf` 是 PHP 的另一个函数，用于格式化字符串，其中 `%02d` 表示按照两位数字的形式输出，不足两位则在前面补0。最终得到的 `$strTableName` 即为附加后的表名。

相关问题

MFC下unicode编码方式，如何通过ADO方式获取BLOB数据到一个字符串中呢？请写一段MFC代码，谢谢

可以使用 `GetChunk` 函数获取 `BLOB` 数据，并将其存储到 `CString` 变量中。以下是一段示例代码：

// 定义 BLOB 字段的名称和表格名称
const CString strFieldName = "BlobField";
const CString strTableName = "TableName";

// 创建连接字符串
CString strConnString = _T("Provider=SQLOLEDB;Data Source=localhost;Initial Catalog=DatabaseName;Integrated Security=SSPI;");

// 创建 ADO 连接对象
_ConnectionPtr pConn;
pConn.CreateInstance(__uuidof(Connection));
pConn->Open(strConnString, "", "", adConnectUnspecified);

// 创建 ADO 记录集对象
_RecordsetPtr pRs;
pRs.CreateInstance(__uuidof(Recordset));

// 打开指定表格
pRs->Open(strTableName, pConn.GetInterfacePtr(), adOpenKeyset, adLockOptimistic, adCmdTable);

// 获取 BLOB 数据
_variant_t varData = pRs->Fields->Item[strFieldName]->Value;
if (varData.vt == VT_NULL) {
    // 如果该字段为空，则执行相应的操作
} else {
    // 将 BLOB 数据存储到一个 CString 对象中
    CString strBlob;
    BYTE* pData = (BYTE*)varData.parray->pvData;
    long lSize = varData.parray->rgsabound[0].cElements;
    long lOffset = 0;
    long lChunkSize = 4096;  // 每次获取的数据块大小
    while (lOffset < lSize) {
        long lRemaining = lSize - lOffset;
        if (lRemaining < lChunkSize) {
            lChunkSize = lRemaining;
        }
        _variant_t varChunk = pRs->Fields->Item[strFieldName]->GetChunk(lChunkSize, lOffset);
        if (varChunk.vt == VT_NULL) {
            // 如果获取数据块失败，则执行相应的操作
            break;
        } else {
            strBlob.Append((LPCSTR)varChunk.pbVal, varChunk.parray->rgsabound[0].cElements);
            lOffset += varChunk.parray->rgsabound[0].cElements;
        }
    }
}

// 关闭记录集和连接
pRs->Close();
pConn->Close();

注意：上述代码假设 BLOB 数据的编码方式为 ANSI，如果是 Unicode 编码，则需要将 `CString` 对象改为 `CStringW` 对象，并将字符串的转换方式改为 `WideCharToMultiByte`。

如何使用win32在指定名字的数据表中创建子表 并重命名子表

你可以使用Win32 API函数来在指定的Access数据表中创建子表并重命名子表。以下是可以用于创建子表并重命名子表的VBA代码：

Option Compare Database
Option Explicit

' Declare Win32 API functions
Private Declare Function CreateTable Lib "dao360.dll" (ByVal db As Long, ByVal Name As String, Optional ByVal Attributes As Long = 0&) As Long
Private Declare Function CreateField Lib "dao360.dll" (ByVal TableDef As Long, ByVal Name As String, ByVal Type As Integer, Optional ByVal Size As Long = 0&, Optional ByVal Attributes As Long = 0&) As Long
Private Declare Function CreateIndex Lib "dao360.dll" (ByVal TableDef As Long, ByVal Name As String, Optional ByVal PrimaryKey As Boolean = False, Optional ByVal Unique As Boolean = False, Optional ByVal Clustered As Boolean = False) As Long
Private Declare Function Append Lib "dao360.dll" (ByVal TableDefs As Long, ByVal Object As Long) As Long
Private Declare Function Rename Lib "dao360.dll" (ByVal TableDef As Long, ByVal Name As String) As Long

Public Sub CreateSubTable()

    Dim db As DAO.Database
    Dim tdf As DAO.TableDef
    Dim fld As DAO.Field
    Dim idx As DAO.Index
    Dim rel As DAO.Relation
    Dim strTableName As String
    Dim strFieldName As String
    
    ' Set table and field names
    strTableName = "MainTable"
    strFieldName = "SubTableID"
    
    ' Open database
    Set db = CurrentDb
    
    ' Create subtable
    Set tdf = db.CreateTableDef(strTableName & "_" & strFieldName)
    CreateTable db.hDb, tdf.Name
    
    ' Add fields to subtable
    Set fld = tdf.CreateField(strFieldName, dbLong)
    CreateField tdf.hTableDef, fld.Name, fld.Type, fld.Size, fld.Attributes
    tdf.Fields.Append fld
    
    ' Add index to subtable
    Set idx = tdf.CreateIndex("PrimaryKey")
    idx.Primary = True
    idx.Fields.Append fld
    CreateIndex tdf.hTableDef, idx.Name, idx.Primary, idx.Unique, idx.Clustered
    tdf.Indexes.Append idx
    
    ' Append subtable to database
    Append db.TableDefs.hTableDefs, tdf.hTableDef
    
    ' Create relationship between main table and subtable
    Set rel = db.CreateRelation("MainTable_SubTable", strTableName, strTableName & "_" & strFieldName)
    rel.Fields.Append rel.CreateField(strFieldName)
    rel.ForeignTable = strTableName
    rel.Attributes = dbRelationDeleteCascade
    db.Relations.Append rel
    
    ' Rename subtable
    Rename tdf.hTableDef, "NewSubTableName"
    
End Sub

这段代码会在名为"MainTable"的数据表中创建一个名为"MainTable_SubTableID"的子表，包含一个名为"SubTableID"的字段，并且将子表重命名为"NewSubTableName"。请根据自己的需要修改表名和字段名。