esent,c++ 接口实例详解
esent是微軟的一個小型数据库，但不支持sql,支持事务以及其他高级功能。下面是我辛苦整理出来的例子，应该不夸张的说，市面上很难找到比这个更全的c++代码了，特别一提的是JetIntersectIndexes这个重要的函数，网上似乎没有人说到关键点，包括managed esent
class JetTest
{
public:
void init()
{
JetCreateInstance(&instance, "EsentPerf");
JetSetSystemParameter(&instance, JET_sesidNil, JET_paramCircularLog, 1, NULL);
JetSetSystemParameter(&instance, JET_sesidNil, JET_paramLogFileSize, 4*1024, NULL); // in KB
JetSetSystemParameter(&instance, JET_sesidNil, JET_paramLogBuffers, 4*1024, NULL); // in 512-bye units
JetInit(&instance);
JetBeginSession(instance, &sesid, 0, 0);
}
bool open_db()
{
int err=JetAttachDatabase(sesid,"esentperftest.db",0);
err=JetOpenDatabase(sesid,"esentperftest.db",NULL,&dbid,0);
if(err!=JET_errSuccess)
{
return false;
}
JetOpenTable(sesid, dbid, "table", NULL, 0, 0, &tableid);
get_colid();
return true;
}
bool create_db()
{
JET_COLUMNDEF columndef = {0};
JetCreateDatabase(sesid, "esentperftest.db", 0, &dbid, 0);
JetBeginTransaction(sesid);
JetCreateTable(sesid, dbid, "table", 0, 100, &tableid);
columndef.cbStruct = sizeof(columndef);
columndef.coltyp = JET_coltypCurrency;//64位整数
JetAddColumn(sesid, tableid, "Key", &columndef, NULL, 0, &columnidKey);
columndef.coltyp = JET_coltypText;
columndef.cbMax=10;
JetAddColumn(sesid, tableid, "Data", &columndef, NULL, 0, &columnidData);
err=JetCreateIndex(sesid, tableid, "primary", JET_bitIndexPrimary|JET_bitIndexUnique, "+data\0+key\0", 12, 100);
err=JetCreateIndex(sesid, tableid, "idx_key", 0, "+key\0",6, 100);
err=JetCreateIndex(sesid, tableid, "idx_data", 0, "+data\0",7,100);
JetCommitTransaction(sesid, 0);
get_colid();
insert();
return true;
}
void get_colid()
{
{
JET_COLUMNDEF col;
JetGetColumnInfo(sesid,dbid,"table","Key",&col,sizeof(col),JET_ColInfo);
columnidKey=col.columnid;
}
{
JET_COLUMNDEF col;
JetGetColumnInfo(sesid,dbid,"table","Data",&col,sizeof(col),JET_ColInfo);
columnidData=col.columnid;
}
}
void insert()
{
JetBeginTransaction(sesid);
for(__int64 day=20120601;day<20120630;day++)
{
for(int i=600000;i<600300;i++)
{
JetPrepareUpdate(sesid, tableid, JET_prepInsert);
char buf;
int len=sprintf(buf,"SH%d",i);
JET_SETCOLUMN setcolumns[] =
{
{ columnidKey, &day, sizeof(day), 0, 0, 1, JET_errSuccess },
{ columnidData, buf, len, 0, 0, 1, JET_errSuccess },
};
err=JetSetColumns(sesid, tableid, setcolumns, _countof(setcolumns));
err=JetUpdate(sesid, tableid, NULL, 0, NULL);
}
}
JetCommitTransaction(sesid, 0);
}
void select()
{
__int64 key;
unsigned char data={0};
JET_RETRIEVECOLUMN retcolumns[] =
{
{ columnidKey, &key, sizeof(key), 0, 0, 0, 1, 0, JET_errSuccess },
{ columnidData, data, sizeof(data), 0, 0, 0, 1, 0, JET_errSuccess },
};
JetMove(sesid, tableid, JET_MoveFirst, 0);
while(true)
{
JetBeginTransaction(sesid);
if(JET_errSuccess==JetRetrieveColumns(sesid, tableid, retcolumns, _countof(retcolumns)))
{
printf("%I64d %s\n",key,data);
}
JetCommitTransaction(sesid, 0);
if(JET_errSuccess != JetMove(sesid, tableid, JET_MoveNext, 0))
break;
}
}
void search1()
{
__int64 key=0;
char data={0};
int datalen=sprintf(data,"SH600002");
JetBeginTransaction(sesid);
err=JetSetCurrentIndex(sesid,tableid,NULL);
err=JetMakeKey(sesid, tableid, data, datalen, JET_bitNewKey);
err=JetMakeKey(sesid, tableid, &key, sizeof(key), 0);
err=JetSeek(sesid, tableid, JET_bitSeekGE);
if((err==JET_errSuccess)||(err==JET_wrnSeekNotEqual))
{
key=0;
memset(data,0,sizeof(data));
JET_RETRIEVECOLUMN retcolumns[] =
{
{ columnidKey, &key, sizeof(key), 0, 0, 0, 1, 0, JET_errSuccess },
{ columnidData, data, sizeof(data), 0, 0, 0, 1, 0, JET_errSuccess },
};
JetRetrieveColumns(sesid, tableid, retcolumns, _countof(retcolumns));
}
JetCommitTransaction(sesid, 0);
printf("we find it!!!\n");
}
void search2()
{
__int64 key=12;
char data={0};
int datalen=sprintf(data,"%I64d",0);
JetBeginTransaction(sesid);
err=JetSetCurrentIndex(sesid,tableid,NULL);
err=JetMakeKey(sesid, tableid, &key, sizeof(key), JET_bitNewKey);
err=JetMakeKey(sesid, tableid, data, datalen, 0);
err=JetSeek(sesid, tableid, JET_bitSeekGT);
key=24;
err=JetMakeKey(sesid, tableid, &key, sizeof(key), JET_bitNewKey);
err=JetMakeKey(sesid, tableid, data, datalen, 0);
//err=JetSeek(sesid, tableid, JET_bitSeekLT);
err=JetSetIndexRange(sesid,tableid,JET_bitRangeInclusive|JET_bitRangeUpperLimit);
JET_RETRIEVECOLUMN retcolumns[] =
{
{ columnidKey, &key, sizeof(key), 0, 0, 0, 1, 0, JET_errSuccess },
{ columnidData, data, sizeof(data), 0, 0, 0, 1, 0, JET_errSuccess },
};
while(true)
{
JetBeginTransaction(sesid);
JetRetrieveColumns(sesid, tableid, retcolumns, _countof(retcolumns));
JetCommitTransaction(sesid, 0);
if(JET_errSuccess != JetMove(sesid, tableid, JET_MoveNext, 0))
break;
}
}
void search3()
{
JET_TABLEID newtable;
err=JetOpenTable(sesid, dbid, "table", NULL, 0, 0, &newtable);
{
int curtable=newtable;
__int64 key=20120602;
err=JetSetCurrentIndex(sesid,curtable,"idx_key");
err=JetMakeKey(sesid,curtable,&key,sizeof(key),JET_bitNewKey);
err=JetSeek(sesid, curtable, JET_bitSeekGE);
key=20120612;
err=JetMakeKey(sesid,curtable,&key,sizeof(key),JET_bitNewKey);
err=JetSetIndexRange(sesid,curtable,JET_bitRangeInclusive|JET_bitRangeUpperLimit);
}
//err=JetDupCursor(sesid,tableid,&newtable,0);
{
int curtable=tableid;
char data={0};
int datalen=sprintf(data,"SH600002");
err=JetSetCurrentIndex(sesid,curtable,"idx_data");
err=JetMakeKey(sesid,curtable,data,datalen,JET_bitNewKey);
err=JetSeek(sesid, curtable, JET_bitSeekGE);
datalen=sprintf(data,"SH600004");
err=JetMakeKey(sesid,curtable,data,datalen,JET_bitNewKey);
err=JetSetIndexRange(sesid,curtable,JET_bitRangeInclusive|JET_bitRangeUpperLimit);
}
JET_INDEXRANGE ir;
memset(ir,0,sizeof(ir));
ir.cbStruct=sizeof(JET_INDEXRANGE);
ir.tableid=tableid;
ir.grbit=JET_bitRecordInIndex;
ir.cbStruct=sizeof(JET_INDEXRANGE);
ir.tableid=newtable;
ir.grbit=JET_bitRecordInIndex;
JET_RECORDLIST recs;
memset(&recs,0,sizeof(recs));
recs.cbStruct=sizeof(recs);
err=JetIntersectIndexes(sesid,ir,2,&recs,0);
__int64 key=12;
char data={0};
JET_RETRIEVECOLUMN retcolumns[] =
{
{ columnidKey, &key, sizeof(key), 0, 0, 0, 1, 0, JET_errSuccess },
{ columnidData, data, sizeof(data), 0, 0, 0, 1, 0, JET_errSuccess },
};
err=JetMove(sesid, recs.tableid, JET_MoveFirst,0);
while(err==JET_errSuccess)
{
char buf;
unsigned long actlen=sizeof(buf);
err=JetRetrieveColumn(sesid,recs.tableid,recs.columnidBookmark,buf,sizeof(buf),&actlen,0,NULL);
printf("%I64d,%s\n",key,data);
err=JetGotoBookmark(sesid,tableid,buf,actlen);
err=JetRetrieveColumns(sesid, tableid, retcolumns, _countof(retcolumns));
err=JetMove(sesid, recs.tableid, JET_MoveNext,0);
}
}
public:
JET_INSTANCE instance;
JET_SESID sesid;
JET_DBID dbid;
JET_TABLEID tableid;
JET_COLUMNID columnidKey;
JET_COLUMNID columnidData;
int err;
};
这个东东的优势在于性能，我想在i3机器上一秒插入１万条数据应该不是什么难事情。 最后一个函数search3为多个索引联合查询。 无私的奉献啊，这东西就是太偏门了，不过我也讨厌SQL哈哈 实测结果性能比sqlite强多了。
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