1 files changed, 93 insertions, 0 deletions
diff --git a/tests/niminaction/Chapter7/Tweeter/src/database.nim b/tests/niminaction/Chapter7/Tweeter/src/database.nim
new file mode 100644
index 000000000..bd6667f70
--- /dev/null
+++ b/tests/niminaction/Chapter7/Tweeter/src/database.nim
@@ -0,0 +1,93 @@
+import times, db_sqlite, strutils #<1>
+type #<2>
+  Database* = ref object
+    db*: DbConn
+
+  User* = object #<3>
+    username*: string #<4>
+    following*: seq[string] #<5>
+
+  Message* = object #<6>
+    username*: string #<7>
+    time*: Time #<8>
+    msg*: string #<9>
+
+proc newDatabase*(filename = "tweeter.db"): Database =
+  new result
+  result.db = open(filename, "", "", "")
+
+proc close*(database: Database) =
+ database.db.close()
+
+proc setup*(database: Database) =
+  database.db.exec(sql"""
+    CREATE TABLE IF NOT EXISTS User(
+      username text PRIMARY KEY
+    );
+  """)
+
+  database.db.exec(sql"""
+    CREATE TABLE IF NOT EXISTS Following(
+      follower text,
+      followed_user text,
+      PRIMARY KEY (follower, followed_user),
+      FOREIGN KEY (follower) REFERENCES User(username),
+      FOREIGN KEY (followed_user) REFERENCES User(username)
+    );
+  """)
+
+  database.db.exec(sql"""
+    CREATE TABLE IF NOT EXISTS Message(
+      username text,
+      time integer,
+      msg text NOT NULL,
+      FOREIGN KEY (username) REFERENCES User(username)
+    );
+  """)
+
+proc post*(database: Database, message: Message) =
+  if message.msg.len > 140: #<1>
+    raise newException(ValueError, "Message has to be less than 140 characters.")
+
+  database.db.exec(sql"INSERT INTO Message VALUES (?, ?, ?);", #<2>
+    message.username, $message.time.toUnix().int, message.msg) #<3>
+
+proc follow*(database: Database, follower: User, user: User) =
+  database.db.exec(sql"INSERT INTO Following VALUES (?, ?);",#<2>
+    follower.username, user.username)
+
+proc create*(database: Database, user: User) =
+  database.db.exec(sql"INSERT INTO User VALUES (?);", user.username) #<2>
+
+proc findUser*(database: Database, username: string, user: var User): bool =
+  let row = database.db.getRow(
+      sql"SELECT username FROM User WHERE username = ?;", username)
+  if row[0].len == 0: return false
+  else: user.username = row[0]
+
+  let following = database.db.getAllRows(
+      sql"SELECT followed_user FROM Following WHERE follower = ?;", username)
+  user.following = @[]
+  for row in following:
+    if row[0].len != 0:
+      user.following.add(row[0])
+
+  return true
+
+proc findMessages*(database: Database, usernames: seq[string],
+    limit = 10): seq[Message] =
+  result = @[]
+  if usernames.len == 0: return
+  var whereClause = " WHERE "
+  for i in 0 ..< usernames.len:
+    whereClause.add("username = ? ")
+    if i != usernames.high:
+      whereClause.add("or ")
+
+  let messages = database.db.getAllRows(
+      sql("SELECT username, time, msg FROM Message" &
+          whereClause &
+          "ORDER BY time DESC LIMIT " & $limit),
+      usernames)
+  for row in messages:
+    result.add(Message(username: row[0], time: fromUnix(row[1].parseInt), msg: row[2]))