README.md in csvsql-0.1.5 vs README.md in csvsql-0.2.0
- old
+ new
@@ -5,10 +5,14 @@
[](https://badge.fury.io/rb/csvsql)
Use SQL to query your CSV file, and return a new CSV.
+## Requirements
+
+* SQlite 3.6.16 or newer.
+
## Installation
Add this line to your application's Gemfile:
```ruby
@@ -73,16 +77,30 @@
# 2
```
### Cache CSV data
-It will save the CSV data to a tempfile. we use `~/.csvsql_cache` folder to save the cache
+It will save the parsed data to `~/.csvsql_cache` folder. it will not parse data again next time if the data file didn't change
```
csvsql -i large.csv -c "select count(*) from csv"
# the second, it will be fast.
csvsql -i large.csv -c "select count(*) from csv"
+```
+
+### Query multiple CSV files
+
+For multiple files, we should name each files. This name will be a `table name`.
+
+```
+csvsql -i users.csv:users -i posts.csv:posts "select * from posts join users on posts.user_id = users.id where users.role = 'guest'"
+```
+
+With cache. those name will be a `database name`, the table name is `csv`. If a csv file was updated, that db will be update only. Other db still use cache.
+
+```
+csvsql -i users.csv:users -i posts.csv:posts -c "select * from posts.csv join users.csv on posts.csv.user_id = users.csv.id where users.csv.role = 'guest'"
```
### Clear Cache
This command will remove all data in the `~/.csvsql_cache`