sql - 数据库被锁定在 R

Question

在 R 中，我正在使用以下函数，该函数在该函数中使用 3 或 4 个数据库操作。但是显示如下错误消息:

Error in sqliteExecStatement(conn, statement, ...) : 
  RS-DBI driver: (RS_SQLite_exec: could not execute1: database is locked)

我需要对我的代码进行哪些修改？我的代码如下:

library('RSQLite')
test <- function(portfolio,date,frame){
  lite <- dbDriver("SQLite", max.con = 25)
  db <- dbConnect(lite, dbname = "portfolioInfo1.db")
  sql <- paste("SELECT *  from ", portfolio," where portDate='", date, "' ", sep = "")
  res <- dbSendQuery(db, sql)
  data <- fetch(res)
  frame1 <- data.frame(portDate=date,frame)

 lite <- dbDriver("SQLite", max.con = 25)
 db <- dbConnect(lite, dbname = "portfolioInfo1.db")
  sql <- paste("delete from ", portfolio," where portDate='", date, "' ", sep = "")
 res <- dbSendQuery(db, sql)

  lite <- dbDriver("SQLite", max.con = 25)
  db <- dbConnect(lite, dbname = "portfolioInfo1.db")
  dbWriteTable(db,portfolio,frame1,append=TRUE,row.names=FALSE) 
}
tick <- c("AAPL","TH","YHOO")
quant <- c("121","1313","131313131")
frame <-data.frame(ticker=tick,quantities=quant)
#print(frame)
test("RUSEG","2006-02-28",frame)

Answer 1

您似乎多次连接到同一个数据库而没有断开连接。如果建立连接以防止其他人编辑已被编辑的数据库，则数据库可能会进入锁定状态。

每次连接后断开连接，或者只连接一次，执行所有查询，然后最终断开连接。