5 files changed, 147 insertions, 8 deletions
diff --git a/lib/impure/db_mysql.nim b/lib/impure/db_mysql.nim
index 170fee8b8..1b7f1de61 100644
--- a/lib/impure/db_mysql.nim
+++ b/lib/impure/db_mysql.nim
@@ -10,7 +10,49 @@
 ## A higher level `mySQL`:idx: database wrapper. The same interface is
 ## implemented for other databases too.
 ##
-## Example:
+## See also: `db_odbc <db_odbc.html>`_, `db_sqlite <db_sqlite.html>`_,
+## `db_postgres <db_postgres.html>`_.
+##
+## Parameter substitution
+## ----------------------
+##
+## All ``db_*`` modules support the same form of parameter substitution.
+## That is, using the ``?`` (question mark) to signify the place where a
+## value should be placed. For example:
+##
+## .. code-block:: Nim
+##     sql"INSERT INTO myTable (colA, colB, colC) VALUES (?, ?, ?)"
+##
+##
+## Examples
+## --------
+##
+## Opening a connection to a database
+## ==================================
+##
+## .. code-block:: Nim
+##     import db_mysql
+##     let db = open("localhost", "user", "password", "dbname")
+##     db.close()
+##
+## Creating a table
+## ================
+##
+## .. code-block:: Nim
+##      db.exec(sql"DROP TABLE IF EXISTS myTable")
+##      db.exec(sql("""CREATE TABLE myTable (
+##                       id integer,
+##                       name varchar(50) not null)"""))
+##
+## Inserting data
+## ==============
+##
+## .. code-block:: Nim
+##     db.exec(sql"INSERT INTO myTable (id, name) VALUES (0, ?)",
+##             "Dominik")
+##
+## Larger example
+## ==============
 ##
 ## .. code-block:: Nim
 ##
diff --git a/lib/impure/db_odbc.nim b/lib/impure/db_odbc.nim
index 6af69d842..4f0b0469d 100644
--- a/lib/impure/db_odbc.nim
+++ b/lib/impure/db_odbc.nim
@@ -11,12 +11,54 @@
 ##
 ## This is the same interface that is implemented for other databases.
 ##
-## This has NOT yet been (extensively) tested agains ODBC drivers for
-## Teradata, Oracle, Sybase, MSSqlvSvr, et. al.  databases
+## This has NOT yet been (extensively) tested against ODBC drivers for
+## Teradata, Oracle, Sybase, MSSqlvSvr, et. al.  databases.
 ##
 ## Currently all queries are ANSI calls, not Unicode.
 ##
-## Example:
+## See also: `db_postgres <db_postgres.html>`_, `db_sqlite <db_sqlite.html>`_,
+## `db_mysql <db_mysql.html>`_.
+##
+## Parameter substitution
+## ----------------------
+##
+## All ``db_*`` modules support the same form of parameter substitution.
+## That is, using the ``?`` (question mark) to signify the place where a
+## value should be placed. For example:
+##
+## .. code-block:: Nim
+##     sql"INSERT INTO myTable (colA, colB, colC) VALUES (?, ?, ?)"
+##
+##
+## Examples
+## --------
+##
+## Opening a connection to a database
+## ==================================
+##
+## .. code-block:: Nim
+##     import db_odbc
+##     let db = open("localhost", "user", "password", "dbname")
+##     db.close()
+##
+## Creating a table
+## ================
+##
+## .. code-block:: Nim
+##      db.exec(sql"DROP TABLE IF EXISTS myTable")
+##      db.exec(sql("""CREATE TABLE myTable (
+##                       id integer,
+##                       name varchar(50) not null)"""))
+##
+## Inserting data
+## ==============
+##
+## .. code-block:: Nim
+##     db.exec(sql"INSERT INTO myTable (id, name) VALUES (0, ?)",
+##             "Andreas")
+##
+## Large example
+## =============
 ##
 ## .. code-block:: Nim
 ##
diff --git a/lib/impure/db_postgres.nim b/lib/impure/db_postgres.nim
index 9bdbae4c2..60bd1f081 100644
--- a/lib/impure/db_postgres.nim
+++ b/lib/impure/db_postgres.nim
@@ -10,6 +10,9 @@
 ## A higher level `PostgreSQL`:idx: database wrapper. This interface
 ## is implemented for other databases also.
 ##
+## See also: `db_odbc <db_odbc.html>`_, `db_sqlite <db_sqlite.html>`_,
+## `db_mysql <db_mysql.html>`_.
+##
 ## Parameter substitution
 ## ----------------------
 ##
@@ -27,7 +30,7 @@
 ##
 ## 2. ``SqlPrepared`` using ``$1, $2, $3, ...``
 ##
-##  .. code-block:: Nim
+## .. code-block:: Nim
 ##   prepare(db, "myExampleInsert",
 ##           sql"""INSERT INTO myTable
 ##                 (colA, colB, colC)
@@ -162,8 +165,10 @@ proc setupQuery(db: DbConn, stmtName: SqlPrepared,
 
 proc prepare*(db: DbConn; stmtName: string, query: SqlQuery;
               nParams: int): SqlPrepared =
+  ## Creates a new ``SqlPrepared`` statement. Parameter substitution is done
+  ## via ``$1``, ``$2``, ``$3``, etc.
   if nParams > 0 and not string(query).contains("$1"):
-    dbError("""parameter substitution expects "$1" """)
+    dbError("parameter substitution expects \"$1\"")
   var res = pqprepare(db, stmtName, query.string, int32(nParams), nil)
   if pqResultStatus(res) != PGRES_COMMAND_OK: dbError(db)
   return SqlPrepared(stmtName)
@@ -282,6 +287,15 @@ proc getValue*(db: DbConn, query: SqlQuery,
   var x = pqgetvalue(setupQuery(db, query, args), 0, 0)
   result = if isNil(x): "" else: $x
 
+proc getValue*(db: DbConn, stmtName: SqlPrepared,
+               args: varargs[string, `$`]): string {.
+               tags: [ReadDbEffect].} =
+  ## executes the query and returns the first column of the first row of the
+  ## result dataset. Returns "" if the dataset contains no rows or the database
+  ## value is NULL.
+  var x = pqgetvalue(setupQuery(db, stmtName, args), 0, 0)
+  result = if isNil(x): "" else: $x
+
 proc tryInsertID*(db: DbConn, query: SqlQuery,
                   args: varargs[string, `$`]): int64 {.
                   tags: [WriteDbEffect].}=
diff --git a/lib/impure/db_sqlite.nim b/lib/impure/db_sqlite.nim
index c0d221a0d..1633d48f7 100644
--- a/lib/impure/db_sqlite.nim
+++ b/lib/impure/db_sqlite.nim
@@ -10,7 +10,48 @@
 ## A higher level `SQLite`:idx: database wrapper. This interface
 ## is implemented for other databases too.
 ##
-## Example:
+## See also: `db_odbc <db_odbc.html>`_, `db_postgres <db_postgres.html>`_,
+## `db_mysql <db_mysql.html>`_.
+##
+## Parameter substitution
+## ----------------------
+##
+## All ``db_*`` modules support the same form of parameter substitution.
+## That is, using the ``?`` (question mark) to signify the place where a
+## value should be placed. For example:
+##
+## .. code-block:: Nim
+##     sql"INSERT INTO myTable (colA, colB, colC) VALUES (?, ?, ?)"
+##
+## Examples
+## --------
+##
+## Opening a connection to a database
+## ==================================
+##
+## .. code-block:: Nim
+##     import db_sqlite
+##     let db = open("localhost", "user", "password", "dbname")
+##     db.close()
+##
+## Creating a table
+## ================
+##
+## .. code-block:: Nim
+##      db.exec(sql"DROP TABLE IF EXISTS myTable")
+##      db.exec(sql("""CREATE TABLE myTable (
+##                       id integer,
+##                       name varchar(50) not null)"""))
+##
+## Inserting data
+## ==============
+##
+## .. code-block:: Nim
+##     db.exec(sql"INSERT INTO myTable (id, name) VALUES (0, ?)",
+##             "Jack")
+##
+## Larger example
+## ==============
 ##
 ## .. code-block:: nim
 ##
diff --git a/lib/impure/rdstdin.nim b/lib/impure/rdstdin.nim
index b373859f4..15137b436 100644
--- a/lib/impure/rdstdin.nim
+++ b/lib/impure/rdstdin.nim
@@ -100,7 +100,7 @@ when defined(Windows):
     stdout.write "\n"
 
 else:
-  import linenoise, termios, unsigned
+  import linenoise, termios
 
   proc readLineFromStdin*(prompt: string): TaintedString {.
                           tags: [ReadIOEffect, WriteIOEffect].} =