next.jdbc — seancorfield/next.jdbc 1.0.0-alpha8

The public API of the next generation java.jdbc library.

The basic building blocks are the java.sql/javax.sql classes:

• DataSource -- something to get connections from,
• Connection -- an active connection to the database,
• PreparedStatement -- SQL and parameters combined, from a connection,

and the following functions and a macro:

• reducible! -- given a connectable and SQL + parameters or a statement, return a reducible that, when reduced will execute the SQL and consume the ResultSet produced,
• execute! -- given a connectable and SQL + parameters or a statement, execute the SQL, consume the ResultSet produced, and return a vector of hash maps representing the rows (@1); this can be datafied to allow navigation of foreign keys into other tables (either by convention or via a schema definition),
• execute-one! -- given a connectable and SQL + parameters or a statement, execute the SQL, consume the first row of the ResultSet produced, and return a hash map representing that row; this can be datafied to allow navigation of foreign keys into other tables (either by convention or via a schema definition),
• prepare -- given a Connection and SQL + parameters, construct a new PreparedStatement; in general this should be used with with-open,
• transact -- the functional implementation of with-transaction,
• with-transaction -- execute a series of SQL operations within a transaction.

@1 result sets are built, by default, as vectors of hash maps, containing qualified keywords as column names, but the row builder and result set builder machinery is open and alternatives are provided to produce unqualified keywords as column names, and to produce a vector the column names followed by vectors of column values for each row, and lower-case variants of each.

The following options are supported wherever a PreparedStatement is created:

• :concurrency -- :read-only, :updatable,
• :cursors -- :close, :hold
• :fetch-size -- the fetch size value,
• :max-rows -- the maximum number of rows to return,
• :result-type -- :forward-only, :scroll-insensitive, :scroll-sensitive,
• :return-keys -- either true or a vector of key names to return,
• :timeout -- the query timeout.

execute! clj

(execute! stmt)

(execute! connectable sql-params)

(execute! connectable sql-params opts)

General SQL execution function.

Returns a fully-realized result set.

Can be called on a PreparedStatement, a Connection, or something that can produce a Connection via a DataSource.

execute-one! clj

(execute-one! stmt)

(execute-one! connectable sql-params)

(execute-one! connectable sql-params opts)

General SQL execution function that returns just the first row of a result.

Can be called on a PreparedStatement, a Connection, or something that can produce a Connection via a DataSource.

get-connection clj

(get-connection spec)

(get-connection spec opts)

Given some sort of specification of a database, return a new Connection.

In general, this should be used via with-open:

  (with-open [con (get-connection spec opts)]
    (run-some-ops con))

If you call get-connection on a DataSource, it just calls .getConnection and applies the :auto-commit and/or :read-only options, if provided.

If you call get-connection on anything else, it will call get-datasource first to try to get a DataSource, and then call get-connection on that.

get-datasource clj

(get-datasource spec)

Given some sort of specification of a database, return a DataSource.

A specification can be a JDBC URL string (which is passed to the JDBC driver as-is), or a hash map. For the hash map, these keys are required:

• :dbtype -- a string indicating the type of the database
• :dbname -- a string indicating the name of the database to be used

The following optional keys are commonly used:

• :user -- the username to authenticate with
• :password -- the password to authenticate with
• :host -- the hostname or IP address of the database (default: 127.0.0.1)
• :port -- the port for the database connection (the default is database- specific -- see below)
• :classname -- if you need to override the default for the :dbtype (or you want to use a database that next.jdbc does not know about!)

Any additional options provided will be passed to the JDBC driver's .getConnection call as a java.util.Properties structure.

Database types supported, and their defaults:

• derby -- org.apache.derby.jdbc.EmbeddedDriver -- also pass :create true if you want the database to be automatically created
• h2 -- org.h2.Driver -- for an on-disk database
• h2:mem -- org.h2.Driver -- for an in-memory database
• hsqldb, hsql -- org.hsqldb.jdbcDriver
• jtds:sqlserver, jtds -- net.sourceforge.jtds.jdbc.Driver -- 1433
• mysql -- com.mysql.cj.jdbc.Driver, com.mysql.jdbc.Driver -- 3306
• oracle:oci -- oracle.jdbc.OracleDriver -- 1521
• oracle:thin, oracle -- oracle.jdbc.OracleDriver -- 1521
• oracle:sid -- oracle.jdbc.OracleDriver -- 1521 -- uses the legacy : separator for the database name but otherwise behaves like oracle:thin
• postgresql, postgres -- org.postgresql.Driver -- 5432
• pgsql -- com.impossibl.postgres.jdbc.PGDriver -- no default port
• redshift -- com.amazon.redshift.jdbc.Driver -- no default port
• sqlite -- org.sqlite.JDBC
• sqlserver, mssql -- com.microsoft.sqlserver.jdbc.SQLServerDriver -- 1433

prepare clj

(prepare connection sql-params)

(prepare connection sql-params opts)

Given a connection to a database, and a vector containing SQL and any parameters it needs, return a new PreparedStatement.

In general, this should be used via with-open:

  (with-open [stmt (prepare spec sql-params opts)]
    (run-some-ops stmt))

See the list of options above (in the namespace docstring) for what can be passed to prepare.

reducible! clj

(reducible! stmt)

(reducible! connectable sql-params)

(reducible! connectable sql-params opts)

General SQL execution function.

Returns a reducible that, when reduced, runs the SQL and yields the result.

Can be called on a PreparedStatement, a Connection, or something that can produce a Connection via a DataSource.

transact clj

(transact connectable f)

(transact connectable f opts)

Given a connectable object and a function (taking a Connection), execute the function on a new connection in a transactional manner.

See with-transaction for supported options.

with-transaction clj macro

(with-transaction [sym connectable opts] & body)

Given a connectable object, gets a new connection and binds it to sym, then executes the body in that context, committing any changes if the body completes successfully, otherwise rolling back any changes made.

The options map supports:

• :isolation -- :none, :read-committed, :read-uncommitted, :repeatable-read, :serializable,
• :read-only -- true / false,
• :rollback-only -- true / false.