Check existence

Check whether a Key exists in Redis

IDatabase.KeyExists(string key)
Purpose: Check whether the specified key exists in Redis

• Return true: the key exists
• Return false: the key does not exist

It returns true as long as the key exists, works for all data types (applies to String, List, Hash and other types)

/// <summary>
/// Check if cache key exists
/// </summary>
/// <param name="key">Cache key name</param>
/// <returns>true if exists, false if not exists</returns>
private bool IsSet(string key)
{
    return db.KeyExists(key);
}Code language: PHP (php)

Example

string cacheKey = "user:1001";
if(IsSet(cacheKey))
{
    // Key exists, read cache directly
    var user = Get<User>(cacheKey);
}
else
{
    // Key not exists, query database and write to Redis
    var user = QueryDbUser(1001);
    Set(cacheKey, user, 30);
}Code language: JavaScript (javascript)

Check existence