CLI: Do not use CLI as an abbreviation for Command Line Interface. It is a standard abbreviation for Call-Level Interface.

Connection: It is true that connections and sessions are associated, but the word “connection” should not be used when “session” is more accurate. For example: not “a transaction during this connection” but “a transaction during this session.” Indeed, Paul has noted a tendency to use connection, session, client, and thread all to mean roughly the same thing. And with the advent of thread-pooling for handing client connections in MySQL 6.0, it no longer necessarily true that a given connection will be serviced by a given thread. This means the rough synonymy that historically has held true is no longer valid.

Cursor: It is difficult to pin this one down, but it seems that some people might be saying “create a cursor” when they really mean “allocate a statement (stmt).” The word cursor must be reserved for the named object which is the subject of open/fetch/close.

Database: This appears even in the MySQL Reference Manual: “MySQL, the most popular Open Source database ...” Correct is: Database Management System, or DBMS.

Derived table: It is true that, in the following statement, the bit in the FROM clause is a “derived table.”

SELECT * FROM (SELECT * FROM t) AS X;

However, so are many other things. For example, a view is a [named] derived table. Therefore, if you really want to specify that you are using a query in the FROM clause, correct is: Query in the FROM clause.

Field: People are using “field” when they clearly must mean “column”, as in “a field of a table.” Correct is: Column. This will take a while, since the misuse of “field” occurs in MySQL functions and statements.

Paul breaks this rule in the following context: Some SHOW statements display information about table columns. To discuss this output, it's necessary to refer to table columns and columns in the result set of the SHOW statement, which can easily become confusing. It can help to disambiguate this by referring to the fields of the result set and the columns of the table.

Key: The word KEY may refer to a particular value in an index (an “index key”) or to a set of columns which are useful for lookup (a “primary key” or “foreign key”). However, influenced perhaps by MySQL's “KEY(column)” clause in CREATE TABLE, some people are saying “create a key on column1.” They should say “create an index on column1.”

MySQL: Write MySQL without adornment, that is, not as <emphasis>MySQL</emphasis> or <literal>MySQL</literal>.

MySQL Reference Manual: The name of the reference Manual is MySQL Reference Manual. Subsequent references in close proximity can be just Reference Manual or Manual, as long as it is clear what the text is referring to.

Query: A query is a question, look in your dictionary. SELECT may be called a query, but it is not appropriate to call UPDATE a “query.” Also incorrect is: command. Correct is: statement.

Relation: A relation is a set. That is why a relational database is called relational. It isn't because of some “relationship between tables.”

ROWID: The word “rowid” has been used once, by one person, as an apparent synonym for Primary Key. Wrong. We should use rowid only for a physical location.

Subselect: This was okay at one time, but we want to standardize. Correct is: Subquery.

Write Unix, not UNIX.

Unix and Linux: Unless necessary for some specific reason, we treat Unix and Linux as synonymous, with both being covered by the term “Unix”.

URLs ending in a domain name or directory should not have a slash (/) at the end.