DolphinDB中如何删除某只股票某段时间内的数据

Question

我在dolphindb中创建了一个这样的database和table：

login("admin", "123456")

n=1000000
ID=rand(`a1`a2`a3`a4`a5`a6`a7`a8`b1`b2`b3`c1`c2`c3, n)
dates=2017.08.07..2017.08.11
date=rand(dates, n)
x=rand(10.0, n)
t=table(ID, date, x)

if(existsDatabase("dfs://compodb")){
    dropDatabase("dfs://compodb")
}

dbDate = database(, VALUE, 2017.08.07..2017.08.11)
dbID = database(, HASH,  [STRING, 5]);
db = database("dfs://compodb", COMPO, [dbDate, dbID])
pt = db.createPartitionedTable(t, "pt", `date`ID)

我现在想删除2017.08.07至2017.08.11中的ID=`c2的股票的数据，请问应该如何操作比较高效？

Answer 1

可以先定义一个删除某只股票某天的函数，然后用loop或ploop函数，去删除指定时间段内的数据：

def dropCodeData(dbName, tableName, code,day){
    cnt = exec count(*) from loadTable(dbName, tableName) where date=day, ID=code
    if(cnt==0) return;
    hashNumber = hashBucket(code, 5)
    t = select * from loadTable(dbName, tableName) where date=day, hashBucket(ID, 5)=hashNumber
    delete from t where ID = code
    dropPartition(dbName,"/"+temporalFormat(day,"yyyyMMdd")+"/Key"+string(hashNumber))
    loadTable(dbName, tableName).append!(t)
}

//ploop多线程并行删除某只股票多天的记录
ploop(dropCodeData{database("dfs://compodb"), "pt", `c2}, 2017.08.07..2017.08.11)

//loop单线程删除某只股票多天的记录
loop(dropCodeData{database("dfs://compodb"), "pt", `c2}, 2017.08.07..2017.08.11)

//删除某天某只股票的记录
dropCodeData(database("dfs://compodb"), "pt", `c2, 2017.08.10)