Database languages mainly include the following:
1. SQL (Structured Query Language): This is the most commonly used database language, used to manage and operate relational databases. SQL includes data definition language (DDL), data manipulation language (DML), data query language (DQL) and data control language (DCL), which can perform operations such as creating, querying, updating and deleting database records.
2. PL/SQL (Procedural Language/SQL): This is a procedural language developed by Oracle, which combines the data manipulation capabilities of SQL language and the data processing capabilities of procedural language. PL/SQL supports writing complex database applications such as stored procedures, triggers and functions.
3. T-SQL (Transact-SQL): This is an extended SQL language of Microsoft SQL Server, which provides richer functions such as variables, conditional statements and loops, and is particularly suitable for database operations of Microsoft SQL Server.
4. NoSQL query language: For non-relational databases (NoSQL), they usually use their own query languages, such as Mongo Query Language (MQL) of MongoDB and Cassandra Query Language (CQL) of Cassandra. These languages are optimized for querying and managing unstructured or semi-structured data.
In addition, some database management systems (DBMS) have their own specific languages or extensions to support specific database operations and management tasks. When choosing a database language, you need to consider the specific database system, application scenario, and development requirements.