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To create an index in OCaml with SQL, you need to use the appropriate SQL syntax specific to the database engine you are working with. Let's consider an example using SQLite: ```ocaml let create_index = let db = Sqlite3.db_open "my_database.db" in let query = "CREATE INDEX my_index ON my_table (column1, column2)" in Sqlite3.exec db query ``` In ...
Like records, tuples are a composite of other types of data. But instead of naming the components, they are identified by position. Here are some examples of tuples: (1,2,10)(true,"Hello")( [1;2;3],(0.5,'X')) A tuple with two components is called a pair. A tuple with three components is called a triple.
16 sty 2024 · Caqti_type.(. let ( & ) = tup2 in. int & string & string & string & string & string & int & int & string ... ) The thing to be aware of is that is a nested tuple not a 999-tuple or anything. That means you need to supply parameters like: (x.id, (x.name1, (x.name2, (x.something, (...)))))
I have a table containing the fields group_id and group_type and I want to query the table for all the records having any tuple (group id, group type) from a list of tuples. For example, I want to be able to do something like: SELECT *. FROM mytable. WHERE (group_id, group_type) IN (("1234-567", 2), ("4321-765", 3), ("1111-222", 5))
To access specific elements of a tuple without binding them to variables, you can use indexing. Indexing in OCaml starts from 0, so the first element can be accessed with index 0, the second with index 1, and so on. Here is an example:
2 sty 2010 · A tuple is another kind of type in OCaml that programmers can define. Like records, it is a composite of other types of data. But instead of naming the components, they are identified by position. Here are some examples of tuples: A tuple with two components is called a pair.
Tuples. Here is a tuple containing two values, also known as a pair. # (3, 'K');;-: int * char = (3, 'K') That pair contains the integer 3 and the character 'K'; its type is int * char. The * symbol stands for product type. This generalises to tuples with 3 or more elements. For instance, (6.28, true, "hello") has type float * bool * string.
