README.Rmd

---
output: github_document
---

```{r, echo = FALSE}
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#",
  fig.width = 10, fig.height = 5,
  fig.align = "center",
  fig.path  = "man/Figure/",
  dev = 'svg'
)
```

# tidydb2

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## Goals

> 更便捷的访问数据库

建立气象数据库，一行命令查询数据。

## TODO

- [ ] 读取数据的性能测试

- [ ] 添加写入数据的函数

## Installation

```r
remotes::install_github("rpkgs/tidydb2")
```

## Example

```r
## 查找邻近站点的数据
library(tidymet)
st <- st_met2176_hourly
p <- c(116.4, 39.9)
find_near(p, st)
```

```{r}
library(tidydb2)
library(dplyr)
library(Ipaper)

## hourly气象数据
dbinfo <- get_dbInfo("duckdb")
f <- dbinfo$hourly_2020_2022$db
db <- dbase$new(f)
db

site0 = 50246L
date0 <- make_datetime(2022, 1, 1, 0)

# 0.1s可以读回数据, 这里应该是UTC时间
system.time(
  d <- db$tbl |>
    filter(site == site0, date > date0) |>
    select(date, PRS, TEM, RHU, tigan) |>
    collect()
)

print(d)
db$close()
```