What methods are used to create composite indexes in databases?

Databases use multi-column (composite) indexing to create indexes on multiple columns simultaneously. This speeds up queries that filter or sort data based on a combination of these columns.

In Go (Golang), creating indexes directly is not part of the language itself but is implemented at the database level with which the application interacts. However, when working with databases through ORM or drivers, you can create composite indexes using SQL queries or migrations.

Main methods for creating composite indexes:

• SQL query CREATE INDEX listing multiple columns:

  CREATE INDEX idx_name ON table_name (column1, column2);
  

• Using migrations or ORM DSL, for example, in GORM (Go ORM):

  db.Model(&User{}).AddIndex("idx_name", "column1", "column2")
  

Thus, composite indexes are created at the database level, and in Go, you manage them through SQL or ORM tools.