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docs: fix code snippets in SQL Databases page

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am: 95698f127a

Change-Id: Iebfe1b54c173dc78a11fd3aa3aca5024b7cbb74e
This commit is contained in:
Mark Lu
2016-08-25 21:54:42 +00:00
committed by android-build-merger
parent d6a64d788b 95698f127a
commit 6f5cf3fb0d
1 changed files with 27 additions and 29 deletions
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56
docs/html/training/basics/data-storage/databases.jd
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@@ -75,16 +75,14 @@ single table:</p>
<pre>
public final class FeedReaderContract {
// To prevent someone from accidentally instantiating the contract class,
// give it an empty constructor.
public FeedReaderContract() {}
// make the constructor private.
private FeedReaderContract() {}
/* Inner class that defines the table contents */
public static abstract class FeedEntry implements BaseColumns {
public static class FeedEntry implements BaseColumns {
public static final String TABLE_NAME = &quot;entry&quot;;
public static final String COLUMN_NAME_ENTRY_ID = &quot;entryid&quot;;
public static final String COLUMN_NAME_TITLE = &quot;title&quot;;
public static final String COLUMN_NAME_SUBTITLE = &quot;subtitle&quot;;
...
}
}
</pre>
@@ -103,10 +101,8 @@ private static final String COMMA_SEP = &quot;,&quot;;
private static final String SQL_CREATE_ENTRIES =
&quot;CREATE TABLE &quot; + FeedEntry.TABLE_NAME + &quot; (&quot; +
FeedEntry._ID + &quot; INTEGER PRIMARY KEY,&quot; +
FeedEntry.COLUMN_NAME_ENTRY_ID + TEXT_TYPE + COMMA_SEP +
FeedEntry.COLUMN_NAME_TITLE + TEXT_TYPE + COMMA_SEP +
... // Any other options for the CREATE command
&quot; )&quot;;
FeedEntry.COLUMN_NAME_SUBTITLE + TEXT_TYPE + &quot; )&quot;;
private static final String SQL_DELETE_ENTRIES =
&quot;DROP TABLE IF EXISTS &quot; + FeedEntry.TABLE_NAME;
@@ -189,23 +185,22 @@ SQLiteDatabase db = mDbHelper.getWritableDatabase();
// Create a new map of values, where column names are the keys
ContentValues values = new ContentValues();
values.put(FeedEntry.COLUMN_NAME_ENTRY_ID, id);
values.put(FeedEntry.COLUMN_NAME_TITLE, title);
values.put(FeedEntry.COLUMN_NAME_CONTENT, content);
values.put(FeedEntry.COLUMN_NAME_SUBTITLE, subtitle);
// Insert the new row, returning the primary key value of the new row
long newRowId;
newRowId = db.insert(
FeedEntry.TABLE_NAME,
FeedEntry.COLUMN_NAME_NULLABLE,
values);
long newRowId = db.insert(FeedEntry.TABLE_NAME, null, values);
</pre>
<p>The first argument for {@link android.database.sqlite.SQLiteDatabase#insert insert()}
is simply the table name. The second argument provides
the name of a column in which the framework can insert NULL in the event that the
{@link android.content.ContentValues} is empty (if you instead set this to {@code "null"},
then the framework will not insert a row when there are no values).</p>
is simply the table name. </p>
<p>The second argument tells the framework what to do in the event that the
{@link android.content.ContentValues} is empty (i.e., you did not
{@link android.content.ContentValues#put put} any values).
If you specify the name of a column, the framework inserts a row and sets
the value of that column to null. If you specify <code>null</code>, like in this
code sample, the framework does not insert a row when there are no values.</p>
@@ -227,16 +222,19 @@ SQLiteDatabase db = mDbHelper.getReadableDatabase();
String[] projection = {
FeedEntry._ID,
FeedEntry.COLUMN_NAME_TITLE,
FeedEntry.COLUMN_NAME_UPDATED,
...
FeedEntry.COLUMN_NAME_SUBTITLE
};
// Filter results WHERE "title" = 'My Title'
String selection = FeedEntry.COLUMN_NAME_TITLE + &quot; = ?&quot;;
String[] selectionArgs = { &quot;My Title&quot; };
// How you want the results sorted in the resulting Cursor
String sortOrder =
FeedEntry.COLUMN_NAME_UPDATED + " DESC";
FeedEntry.COLUMN_NAME_SUBTITLE + " DESC";
Cursor c = db.query(
FeedEntry.TABLE_NAME, // The table to query
FeedEntry.TABLE_NAME, // The table to query
projection, // The columns to return
selection, // The columns for the WHERE clause
selectionArgs, // The values for the WHERE clause
@@ -280,11 +278,11 @@ immune to SQL injection.</p>
<pre>
// Define 'where' part of query.
String selection = FeedEntry.COLUMN_NAME_ENTRY_ID + &quot; LIKE ?&quot;;
String selection = FeedEntry.COLUMN_NAME_TITLE + &quot; LIKE ?&quot;;
// Specify arguments in placeholder order.
String[] selectionArgs = { String.valueOf(rowId) };
String[] selectionArgs = { &quot;MyTitle&quot; };
// Issue SQL statement.
db.delete(table_name, selection, selectionArgs);
db.delete(FeedEntry.TABLE_NAME, selection, selectionArgs);
</pre>
@@ -305,9 +303,9 @@ SQLiteDatabase db = mDbHelper.getReadableDatabase();
ContentValues values = new ContentValues();
values.put(FeedEntry.COLUMN_NAME_TITLE, title);
// Which row to update, based on the ID
String selection = FeedEntry.COLUMN_NAME_ENTRY_ID + &quot; LIKE ?&quot;;
String[] selectionArgs = { String.valueOf(rowId) };
// Which row to update, based on the title
String selection = FeedEntry.COLUMN_NAME_TITLE + &quot; LIKE ?&quot;;
String[] selectionArgs = { &quot;MyTitle&quot; };
int count = db.update(
FeedReaderDbHelper.FeedEntry.TABLE_NAME,