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https://github.com/cqerl/cqex
Idiomatic Cassandra client for Elixir
https://github.com/cqerl/cqex
cassandra elixir
Last synced: 3 days ago
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Idiomatic Cassandra client for Elixir
- Host: GitHub
- URL: https://github.com/cqerl/cqex
- Owner: cqerl
- License: mit
- Created: 2015-12-20T03:06:35.000Z (about 9 years ago)
- Default Branch: master
- Last Pushed: 2022-05-12T06:33:01.000Z (over 2 years ago)
- Last Synced: 2025-01-30T05:09:23.369Z (10 days ago)
- Topics: cassandra, elixir
- Language: Elixir
- Homepage:
- Size: 65.4 KB
- Stars: 76
- Watchers: 4
- Forks: 19
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# cqex
Modern Cassandra driver for Elixir, using [cqerl][1] underneath.
### Installation
Add `cqex` to your application's mix.exs:
```elixir
defp deps do
[
# ...
{:cqex, "~> 1.0.0"},
# ...
]
end
```
And update your applications list in the project:
```elixir
def application do
[applications: [:cqex]]
end
```
### Usage examples
If you're using a single cluster, in your project's config/config.exs:
****
```elixir
use Mix.Config
config :cqerl,
cassandra_nodes: [{"10.0.0.1", 9042}, {"10.0.0.2", 9042}],
keyspace: "keyspace"
```
Then, create a transient client connection
```elixir
client = CQEx.Client.new!
```
Fetch the complete list of users, and creating a list out of it using `Enum`
```elixir
all_users = client |> CQEx.Query.call!("SELECT * FROM users;") |> Enum.to_list
# => [ list of users... ]
all_users[0]
# => %{ ... first_user ... }
```
Chain queries and using `Stream` and `Enum` to get the result set in small pages.
```elixir
alias CQEx.Query, as: Q
base = %Q{
statement: "INSERT INTO animals (name, legs, friendly) values (?, ?, ?);",
values: %{ legs: 4, friendly: true }
}
^base = Q.new
|> Q.statement("INSERT INTO animals (name, legs, friendly) values (?, ?, ?);")
|> Q.put(:legs, 4)
|> Q.put(:friendly, true)
animals_by_pair = client
|> Q.call!("CREATE TABLE IF NOT EXISTS animals (name text PRIMARY KEY, legs tinyint, friendly boolean);")
|> Q.call!( base |> Q.merge(%{ name: "cat", friendly: false }) )
|> Q.call!( base |> Q.put(:name, "dog") )
|> Q.call!( base |> Q.merge(%{ name: "bonobo", legs: 2 }) )
|> Q.call!("SELECT * FROM animals;")
|> Stream.chunk(2)
animals_by_pair
|> Enum.at(0)
# => [ %{name: "cat", legs: 4, friendly: false}, %{name: "dog", legs: 4, friendly: true} ]
animals_by_pair
|> Enum.to_list
# => [
# [ %{name: "cat", legs: 4, friendly: false}, %{name: "dog", legs: 4, friendly: true} ],
# [ %{name: "bonobo", legs: 2, friendly: true} ]
# ]
```
Use comprehensions on the results of a CQL query
```elixir
for %{ legs: leg_count, name: name, friendly: true } <- Q.call!(client, "SELECT * FROM animals"),
leg_count == 4,
do: "#{name} has four legs"
# => [ "dog has four legs" ]
```
If you want different clusters, in your project's `config/config.exs`:
```elixir
use Mix.Config
config :cqerl,
cassandra_clusters: [
cluster1: { [{"10.0.0.1", 9042}, {"10.0.0.2", 9042}], [keyspace: "keyspace1"] },
cluster2: { [{"10.0.0.1", 9042}, {"10.0.0.2", 9042}], [keyspace: "keyspace2"] }
]
```
Then, in your code
```elixir
client = CQEx.Client.new! :cluster1
# etc
```
[1]: https://github.com/matehat/cqerl/