Coherence Installation and Use
Coherence is an in memory data grid and caching solution used to build high-performance and scalable distributed applications. The following is a detailed introduction to the installation and use of the Coherence database.
1. Install Coherence:
Firstly, you need to download the installation package for Coherence. Can be found on the download page of the Oracle official website（ https://www.oracle.com/middleware/technologies/coherence-downloads.html ）Find the latest version that is suitable for your operating system.
2. Unzip the installation package:
Extract the downloaded installation package to the directory of your choice. After decompressing, you will obtain a coherence directory.
3. Configure environment variables:
In order to access the Coherence tool from any location, it is necessary to add the Coherence bin directory to the system's PATH environment variable. The specific steps vary depending on the operating system.
4. Create a configuration file:
In the coherence directory, you can find an example configuration file called 'default cache config. xml'. You can modify the file according to your own needs or create a brand new configuration file. Save the file in a suitable location, such as the coherence directory.
5. Enable Coherence server:
On the command line, enter the Coherence directory and execute the following command to start the Coherence server:
$ ./coherence.sh -server -Dcoherence.cacheconfig=path/to/your/config.xml
Among them, the 'coherence. cacheconfig' parameter is used to specify the path to the Coherence configuration file.
6. Create a data table:
You can use the Java API provided by Coherence to create data tables. The following is a simple example code snippet for creating a data table called "employees":
import com.tangosol.net.CacheFactory;
import com.tangosol.net.NamedCache;
public class CreateTable {
public static void main(String[] args) {
CacheFactory.ensureCluster();
NamedCache cache = CacheFactory.getCache("employees");
cache.create();
}
}
7. Data insertion:
Using Coherence's API, data can be inserted into a data table. The following is an example code snippet for inserting a record into the 'employees' data table:
import com.tangosol.net.CacheFactory;
import com.tangosol.net.NamedCache;
public class InsertData {
public static void main(String[] args) {
CacheFactory.ensureCluster();
NamedCache cache = CacheFactory.getCache("employees");
cache.put("1", "John Doe");
}
}
8. Data modification:
Coherence's API can be used to modify existing data. The following is an example code snippet for modifying a record in the "employees" data table:
import com.tangosol.net.CacheFactory;
import com.tangosol.net.NamedCache;
public class UpdateData {
public static void main(String[] args) {
CacheFactory.ensureCluster();
NamedCache cache = CacheFactory.getCache("employees");
cache.put("1", "Jane Smith");
}
}
9. Data Query:
Through Coherence's API, records in the data table can be queried. The following is an example code snippet for querying a record in the "employees" data table:
import com.tangosol.net.CacheFactory;
import com.tangosol.net.NamedCache;
public class QueryData {
public static void main(String[] args) {
CacheFactory.ensureCluster();
NamedCache cache = CacheFactory.getCache("employees");
Object result = cache.get("1");
System.out.println(result);
}
}
10. Data deletion:
Using Coherence's API, records in the data table can be deleted. The following is an example code snippet for deleting a record in the "employees" data table:
import com.tangosol.net.CacheFactory;
import com.tangosol.net.NamedCache;
public class DeleteData {
public static void main(String[] args) {
CacheFactory.ensureCluster();
NamedCache cache = CacheFactory.getCache("employees");
cache.remove("1");
}
}
Through the above steps, you can successfully install and use the Coherence database, including creating data tables, inserting, modifying, querying, and deleting data. Please note that this is just a simple example, and Coherence also provides more advanced features and APIs for developers to use.
