Is there any limit on sqlite query size?

Question

Is there any limit on how big the selection statement can be? for example suppose I have 100 failed student as selection, will my below code work?

ArrayList<Long> ids_toupdate = getFailedStudents();// has size 100.
String selection = String.format(Locale.US, STUDENT._ID + " IN (%s)",TextUtils.join(", ", ids_toupdate));
ContentValues cv = new ContentValues();
cv.put(RawContacts.FAILED, 1);
getContentResolver().update(STUDENT.CONTENT_URI,cv, selection, null);

Answer 1

Roughly speaking the default limit is 1,000,000 bytes or 1,000,000 characters, so unless your 'students' are over 100,000 characters each your statement should be fine.

The following is taken from http://www.sqlite.org/limits.html

Maximum Length Of An SQL Statement

The maximum number of bytes in the text of an SQL statement is limited to SQLITE_MAX_SQL_LENGTH which defaults to 1000000. You can redefine this limit to be as large as the smaller of SQLITE_MAX_LENGTH and 1073741824.

If an SQL statement is limited to be a million bytes in length, then obviously you will not be able to insert multi-million byte strings by embedding them as literals inside of INSERT statements. But you should not do that anyway. Use host parameters for your data. Prepare short SQL statements like this:

INSERT INTO tab1 VALUES(?,?,?); 

Then use the sqlite3_bind_XXXX() functions to bind your large string values to the SQL statement. The use of binding obviates the need to escape quote characters in the string, reducing the risk of SQL injection attacks. It is also runs faster since the large string does not need to be parsed or copied as much.

The maximum length of an SQL statement can be lowered at run-time using the sqlite3_limit(db,SQLITE_LIMIT_SQL_LENGTH,size) interface.