Fix bugs where the sample code does not compile and run correctly.

src/database/sqlite/initialization.md

@@ -9,7 +9,6 @@ Use the `rusqlite` crate to open SQLite databases. See
 
 ```rust,edition2018,no_run
 use rusqlite::{Connection, Result};
-use rusqlite::NO_PARAMS;
 
 fn main() -> Result<()> {
     let conn = Connection::open("cats.db")?;
@@ -19,7 +18,7 @@ fn main() -> Result<()> {
              id integer primary key,
              name text not null unique
          )",
-        NO_PARAMS,
+        (),
     )?;
     conn.execute(
         "create table if not exists cats (
@@ -27,7 +26,7 @@ fn main() -> Result<()> {
              name text not null,
              color_id integer not null references cat_colors(id)
          )",
-        NO_PARAMS,
+        (),
     )?;
 
     Ok(())

src/database/sqlite/insert_select.md

@@ -6,8 +6,6 @@
 This recipe inserts data into `cat_colors` and `cats` tables using the [`execute`] method of `Connection`. First, the data is inserted into the `cat_colors` table. After a record for a color is inserted, [`last_insert_rowid`] method of `Connection` is used to get `id` of the last color inserted. This `id` is used while inserting data into the `cats` table. Then, the select query is prepared using the [`prepare`] method which gives a [`statement`] struct. Then, query is executed using [`query_map`] method of [`statement`].
 
 ```rust,no_run
-
-use rusqlite::NO_PARAMS;
 use rusqlite::{Connection, Result};
 use std::collections::HashMap;
 
@@ -44,7 +42,7 @@ fn main() -> Result<()> {
          ON cc.id = c.color_id;",
     )?;
 
-    let cats = stmt.query_map(NO_PARAMS, |row| {
+    let cats = stmt.query_map((), |row| {
         Ok(Cat {
             name: row.get(0)?,
             color: row.get(1)?,

src/database/sqlite/transactions.md

@@ -11,9 +11,8 @@ In the following example, colors add to a table having
 a unique constraint on the color name. When an attempt to insert
 a duplicate color is made, the transaction rolls back.
 
-
 ```rust,edition2018,no_run
-use rusqlite::{Connection, Result, NO_PARAMS};
+use rusqlite::{Connection, Result};
 
 fn main() -> Result<()> {
     let mut conn = Connection::open("cats.db")?;
@@ -29,7 +28,7 @@ fn main() -> Result<()> {
 fn successful_tx(conn: &mut Connection) -> Result<()> {
     let tx = conn.transaction()?;
 
-    tx.execute("delete from cat_colors", NO_PARAMS)?;
+    tx.execute("delete from cat_colors", ())?;
     tx.execute("insert into cat_colors (name) values (?1)", &[&"lavender"])?;
     tx.execute("insert into cat_colors (name) values (?1)", &[&"blue"])?;
 
@@ -39,7 +38,7 @@ fn successful_tx(conn: &mut Connection) -> Result<()> {
 fn rolled_back_tx(conn: &mut Connection) -> Result<()> {
     let tx = conn.transaction()?;
 
-    tx.execute("delete from cat_colors", NO_PARAMS)?;
+    tx.execute("delete from cat_colors", ())?;
     tx.execute("insert into cat_colors (name) values (?1)", &[&"lavender"])?;
     tx.execute("insert into cat_colors (name) values (?1)", &[&"blue"])?;
     tx.execute("insert into cat_colors (name) values (?1)", &[&"lavender"])?;