Connection to a MySQL database.

A query string. This type is intended to make it difficult to construct a SQL query by concatenating string fragments, as that is an extremely common way to accidentally introduce SQL injection vulnerabilities into an application.

This type is an instance of IsString, so the easiest way to construct a query is to enable the OverloadedStrings language extension and then simply write the query in double quotes.

 {-# LANGUAGE OverloadedStrings #-}

 import Database.MySQL.Simple

 q :: Query
 q = "select ?"

Wrap a list of values for use in an IN clause. Replaces a single "?" character with a parenthesized list of rendered values.

Example:

 query "select * from whatever where id in ?" (In [3,4,5])

A single-value collection.

This can be handy if you need to supply a single parameter to a SQL query.

Example:

query "select x from scores where x > ?" (Only (42::Int))

Exception thrown if a Query could not be formatted correctly. This may occur if the number of '?' characters in the query string does not match the number of parameters provided.

Exception thrown if query is used to perform an INSERT-like operation, or execute is used to perform a SELECT-like operation.

Exception thrown if conversion from a SQL value to a Haskell value fails.

Connect to a database.

Default information for setting up a connection.

Defaults are as follows:

• Server on localhost
• User root
• No password
• Database test
• Character set utf8

Use as in the following example:

 connect defaultConnectInfo { connectHost = "db.example.com" }

Close a connection, and mark any outstanding Result as invalid.

Perform a SELECT or other SQL query that is expected to return results.

All results are retrieved and converted before this function returns.

Exceptions that may be thrown:

• FormatError: the query string could not be formatted correctly.
• QueryError: the result contains no columns (i.e. you should be using execute instead of query).
• ResultError: result conversion failed.

A version of query that does not perform query substitution.

Execute an INSERT, UPDATE, or other SQL query that is not expected to return results.

Returns the number of rows affected.

Throws FormatError if the query could not be formatted correctly.

A version of execute that does not perform query substitution.

Execute a multi-row INSERT, UPDATE, or other SQL query that is not expected to return results.

Returns the number of rows affected.

Throws FormatError if the query could not be formatted correctly.

Return the value generated for an AUTO_INCREMENT column by the previous INSERT or UPDATE statement.

See http://dev.mysql.com/doc/refman/5.5/en/mysql-insert-id.html

Execute an action inside a SQL transaction.

You are assumed to have started the transaction yourself.

If your action succeeds, the transaction will be committed before this function returns.

If your action throws any exception (not just a SQL exception), the transaction will be rolled back rollback before the exception is propagated.

Turn autocommit on or off.

By default, MySQL runs with autocommit mode enabled. In this mode, as soon as you modify a table, MySQL stores your modification permanently.

Commit the current transaction.

Roll back the current transaction.

Format a query string with a variable number of rows.

The query string must contain exactly one substitution group, identified by the SQL keyword "VALUES" (case insensitive) followed by an "(" character, a series of one or more "?" characters separated by commas, and a ")" character. White space in a substitution group is permitted.

Throws FormatError if the query string could not be formatted correctly.

Format a query string.

String parameters are escaped according to the character set in use on the Connection.

Throws FormatError if the query string could not be formatted correctly.