SQL Connection String Builder

Q: What is the difference between a JDBC URL and a URI?

A JDBC URL is prefixed with jdbc: and is consumed by Java's JDBC drivers. A native URI (e.g. postgresql://...) is what many non-Java languages expect. They carry the same information in slightly different syntax, this tool generates both.

Q: What are the default SQL database ports?

PostgreSQL 5432, MySQL and MariaDB 3306, SQL Server 1433, Oracle 1521. SQLite is file-based and has no port. If your server uses a custom port, set it explicitly.

More information about SQL connection strings

Connecting to a SQL database requires a well-formed connection string. The exact shape depends on the engine and the driver, a JDBC URL for Java, a native URI for many languages, or an ADO.NET string for .NET. This guide explains the structure, components, and common options, using PostgreSQL as the primary example.

What is a connection string?

A connection string is a single string that tells a database driver how to connect: the server's location, the database name, credentials, and connection options. Java applications typically use a JDBC URL; other ecosystems use a URI or an ADO.NET-style string. This tool generates all of the relevant forms for each engine.

Components of a JDBC URL

General format

jdbc:postgresql://[host]:[port]/[database]?key1=value1&key2=value2

jdbc:, marks this as a JDBC URL.
postgresql, the database type (the sub-protocol / driver).
[host], the hostname or IP address of the server.
[port], the server port; PostgreSQL defaults to 5432.
[database], the name of the database to connect to.
Query parameters, additional connection properties as key=value pairs.

Example

jdbc:postgresql://localhost:5432/mydb?user=myuser&password=mypassword&ssl=true

This connects to the mydb database on localhost as myuser over an SSL connection.

Default ports and schemes by engine

PostgreSQL, port 5432, JDBC jdbc:postgresql://, URI postgresql://.
MySQL / MariaDB, port 3306, JDBC jdbc:mysql:// / jdbc:mariadb://.
SQL Server, port 1433, JDBC jdbc:sqlserver://host:port;databaseName=… (semicolon-separated), plus an ADO.NET form.
Oracle, port 1521, JDBC jdbc:oracle:thin:@//host:port/service (uses a service name, not a database name).
SQLite, file-based, no host or port: jdbc:sqlite:/path/to/database.db.

Common connection parameters

Authentication

user, the username to authenticate with.
password, the password for authentication.

Security

ssl, enable SSL/TLS (true or false).
sslmode (PostgreSQL), disable, require, verify-ca, or verify-full.
sslMode (MySQL) / encrypt (SQL Server), the equivalent per-engine encryption controls.

Performance

connectTimeout, maximum time to wait for a connection to be established.
socketTimeout, maximum time to wait for data on a socket.

Application identification

applicationName, a name for your app, useful in server-side logs and monitoring.
currentSchema, the default schema to use for the connection.

Tips for building a SQL connection string

Verify host and port. Use localhost for a local database or the server's IP/hostname for a remote one, and confirm the port matches the server's configuration.
Secure your credentials. Don't hardcode usernames and passwords in your application, use environment variables or a secrets manager.
Enable SSL in production. Over public networks, set ssl=true and an appropriate sslmode (e.g. verify-full).
Match the driver. A JDBC URL is for Java/JVM tools; other languages usually want the native URI. This tool shows both.
Test before you ship. Validate the string with a client like psql or a GUI before wiring it into your app.

Frequently asked questions

What is the difference between a JDBC URL and a URI?

A JDBC URL is prefixed with jdbc: and is consumed by Java's JDBC drivers. A native URI (e.g. postgresql://…) is what many non-Java languages and libraries expect. They carry the same information in slightly different syntax, this tool generates both.

Can I connect to multiple databases with one string?

No, a connection string targets a single database. To use several databases you create separate connection strings and connections.

What are the default ports?

PostgreSQL 5432, MySQL/MariaDB 3306, SQL Server 1433, Oracle 1521. SQLite is file-based and has no port. If your server uses a custom port, set it explicitly.

How do I debug connection issues?

Confirm the host, port, and credentials, check that firewalls/security groups allow access, and enable verbose logging in your driver or database server to see the underlying error.