Are there any methods that assist with resolving common SQLite issues?
It is often that relatively simple errors cause issues often compounded by a misunderstanding of SQLite.
For example:-
- tables and columns not found be
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Addition 1 - logDatabaseInfo
This will write some information about the Database to the log, for example:-
10-12 06:32:12.426 20575-20575/? D/SQLITE_CSU: DatabaseList Row 1 Name=main File=/data/data/mjt.sqlitedbexamples/databases/eventsDB 10-12 06:32:12.426 20575-20575/? D/SQLITE_CSU: Database Version = 1 10-12 06:32:12.427 20575-20575/? D/SQLITE_CSU: Table Name = android_metadata Created Using = CREATE TABLE android_metadata (locale TEXT) 10-12 06:32:12.427 20575-20575/? D/SQLITE_CSU: Table = android_metadata ColumnName = locale ColumnType = TEXT Default Value = null PRIMARY KEY SEQUENCE = 0 10-12 06:32:12.427 20575-20575/? D/SQLITE_CSU: Table Name = events Created Using = CREATE TABLE events(_id INTEGER PRIMARY KEY, starts INTEGER DEFAULT (strftime('%s','now')),starts_timestamp INTEGER DEFAULT 0,ends INTEGER DEFAULT 0,ends_timestamp INTEGER DEFAULT 0,description TEXT, counter INTEGER DEFAULT 0,bytedata BLOB DEFAULT x'00000000') 10-12 06:32:12.427 20575-20575/? D/SQLITE_CSU: Table = events ColumnName = _id ColumnType = INTEGER Default Value = null PRIMARY KEY SEQUENCE = 1 10-12 06:32:12.427 20575-20575/? D/SQLITE_CSU: Table = events ColumnName = starts ColumnType = INTEGER Default Value = strftime('%s','now') PRIMARY KEY SEQUENCE = 0 10-12 06:32:12.427 20575-20575/? D/SQLITE_CSU: Table = events ColumnName = starts_timestamp ColumnType = INTEGER Default Value = 0 PRIMARY KEY SEQUENCE = 0 10-12 06:32:12.427 20575-20575/? D/SQLITE_CSU: Table = events ColumnName = ends ColumnType = INTEGER Default Value = 0 PRIMARY KEY SEQUENCE = 0 10-12 06:32:12.427 20575-20575/? D/SQLITE_CSU: Table = events ColumnName = ends_timestamp ColumnType = INTEGER Default Value = 0 PRIMARY KEY SEQUENCE = 0 10-12 06:32:12.427 20575-20575/? D/SQLITE_CSU: Table = events ColumnName = description ColumnType = TEXT Default Value = null PRIMARY KEY SEQUENCE = 0 10-12 06:32:12.427 20575-20575/? D/SQLITE_CSU: Table = events ColumnName = counter ColumnType = INTEGER Default Value = 0 PRIMARY KEY SEQUENCE = 0 10-12 06:32:12.427 20575-20575/? D/SQLITE_CSU: Table = events ColumnName = bytedata ColumnType = BLOB Default Value = x'00000000' PRIMARY KEY SEQUENCE = 0The above is for the database name eventsDB, the Version is 1, there are 2 tables android_metadata (required by Apps and automatically generated) and events(actually 3 tables as sqlite_master also exists and is required by SQLite).
The SQL used to create the table is also included for each of the listed tables.
For each table the columns are listed showing the column's name, it's type, it's default value, and it's sequence within the primary index (0 = not in the primary index).
To include logDatabaseInfo replace CommonSQLiteUtilities (or create new) class with the following (note this includes all the other utilities as per orginal answer):-
public class CommonSQLiteUtilities { public static final boolean ERROR_CHECKING_ON = true; public static final boolean ERROR_CHECKING_OFF = false; // SQLite MASTER TABLE definitions static final String SQLITE_MASTER = "sqlite_master"; static final String SM_TABLE_TYPE_COLUMN = "type"; static final String SM_NAME_COLUMN = "name"; static final String SM_TABLENAME_COLUMN = "tbl_name"; static final String SM_ROOTPAGE_COLUMN = "rootpage"; static final String SM_SQL_COLUMN = "sql"; static final String SM_TYPE_TABLE = "table"; static final String SM_TYPE_INDEX = "index"; static final String PRAGMA_STATEMENT = "PRAGMA "; static final String PRAGMA_DATABASELIST = "database_list"; static final String PRAGMA_USERVERSION = "user_version"; static final String PRAGMA_ENCODING = "encoding"; static final String PRAGMA_FOREIGNKEYLIST = "foreign_key_list"; static final String PRAGMA_INDEXINFO = "index_info"; static final String PRAGMA_INDEXLIST = "index_list"; static final String PRAGMA_TABLEINFO = "table_info"; static final String PRAGMA_DBLIST_SEQ_COL = "seq"; static final String PRAGMA_DBLIST_NAME_COL = "name"; static final String PRAGMA_DBLIST_FILE_COL = "file"; static final String PRAGMA_TABLEINFO_CID_COL = "cid"; static final String PRAGMA_TABLEINFO_NAME_COl = "name"; static final String PRAGMA_TABLEINFO_TYPE_COL = "type"; static final String PRAGMA_TABLEINFO_NOTNULL_COL = "notnull"; static final String PRAGMA_TABLEINFO_DEFAULTVALUE_COL = "dflt_value"; static final String PRAGMA_TABLEINFO_PRIMARYKEY_COL = "pk"; static final String CSU_TAG = "SQLITE_CSU"; private CommonSQLiteUtilities() {} /** * Write Database information to the log; * Information wrttien is: * the database path, (will/should show connected databases) * the version number (note! user version i.e. version coded in DBHelper), * the tables in the database (includes android_metadata but not sqlite_master), * the columns of the tables * @param db The SQLite database to be interrogated */ public static void logDatabaseInfo(SQLiteDatabase db) { // Issue PRAGMA database_list commnand Cursor dblcsr = db.rawQuery(PRAGMA_STATEMENT + PRAGMA_DATABASELIST,null); // Write databases to the log while (dblcsr.moveToNext()) { Log.d(CSU_TAG,"DatabaseList Row " + Integer.toString(dblcsr.getPosition() + 1) + " Name=" + dblcsr.getString(dblcsr.getColumnIndex(PRAGMA_DBLIST_NAME_COL)) + " File=" + dblcsr.getString(dblcsr.getColumnIndex(PRAGMA_DBLIST_FILE_COL)) ); } dblcsr.close(); // Issue PRAGMA user_version to get the version and write to the log //Note! to set user_version use execSQL not rawQuery Cursor uvcsr = db.rawQuery(PRAGMA_STATEMENT + PRAGMA_USERVERSION,null); while (uvcsr.moveToNext()) { Log.d(CSU_TAG,"Database Version = " + Integer.toString(uvcsr.getInt(uvcsr.getColumnIndex(PRAGMA_USERVERSION)))); } uvcsr.close(); // Select all table entry rows from sqlite_master Cursor tlcsr = db.rawQuery("SELECT * FROM " + SQLITE_MASTER + " WHERE " + SM_TABLE_TYPE_COLUMN + "='" + SM_TYPE_TABLE + "'" ,null); // For each table write table information to the log // (inner loop gets column info per table) while (tlcsr.moveToNext()) { String current_table = tlcsr.getString(tlcsr.getColumnIndex(SM_TABLENAME_COLUMN)); Log.d(CSU_TAG, "Table Name = " + current_table + " Created Using = " + tlcsr.getString(tlcsr.getColumnIndex(SM_SQL_COLUMN)), null ); // Issue PRAGMA tabel_info for the current table Cursor ticsr = db.rawQuery(PRAGMA_STATEMENT + PRAGMA_TABLEINFO + "(" + current_table + ")", null ); // Write column info (see headings below) to the log while (ticsr.moveToNext()) { Log.d(CSU_TAG,"Table = " + current_table + " ColumnName = " + ticsr.getString(ticsr.getColumnIndex(PRAGMA_TABLEINFO_NAME_COl)) + " ColumnType = " + ticsr.getString(ticsr.getColumnIndex(PRAGMA_TABLEINFO_TYPE_COL)) + " Default Value = " + ticsr.getString(ticsr.getColumnIndex(PRAGMA_TABLEINFO_DEFAULTVALUE_COL)) + " PRIMARY KEY SEQUENCE = " + Integer.toString( ticsr.getInt(ticsr.getColumnIndex(PRAGMA_TABLEINFO_PRIMARYKEY_COL)) ) ); } ticsr.close(); } tlcsr.close(); } /** * Generic get all rows from an SQlite table, * allowing the existence of the table to be checked and also * allowing the ROWID to be added AS a supplied string * * @param db The SQLiteDatabase * @param tablename The name of the table from which the * returned cursor will be created from; * Note! * @param use_error_checking Whether ot not to try to detect errors * currently just table doesn't exist, * true to turn on, false to turn off * ERROR_CHECKING_ON = true * ERROR_CHECKING_OFF = false * @param forceRowidAs If length of string passed is 1 or greater * then a column, as an alias of ROWID, will be * added to the cursor * @return the extracted cursor, or in the case of the * underlying table not existing an empty cursor * with no columns */ public static Cursor getAllRowsFromTable(SQLiteDatabase db, String tablename, boolean use_error_checking, String forceRowidAs) { String[] columns = null; // Tablename must be at least 1 character in length if (tablename.length() < 1) { Log.d(CSU_TAG,new Object(){}.getClass().getEnclosingMethod().getName() + " is finishing as the provided tablename is less than 1 character in length" ); return new MatrixCursor(new String[]{}); } // If use_error_checking is true then check that the table exists // in the sqlite_master table if (use_error_checking) { Cursor chkcsr = db.query(SQLITE_MASTER,null, SM_TABLE_TYPE_COLUMN + "=? AND " + SM_TABLENAME_COLUMN + "=?", new String[]{SM_TYPE_TABLE,tablename}, null,null,null ); // Ooops table is not in the Database so return an empty // column-less cursor if (chkcsr.getCount() < 1) { Log.d(CSU_TAG,"Table " + tablename + " was not located in the SQLite Database Master Table." ); // return empty cursor with no columns return new MatrixCursor(new String[]{}); } chkcsr.close(); } // If forcing an alias of ROWID then user ROWID AS ???, * if(forceRowidAs != null && forceRowidAs.length() > 0) { columns = new String[]{"rowid AS " +forceRowidAs,"*"}; } // Finally return the Cursor but trap any exceptions try { return db.query(tablename, columns, null, null, null, null, null); } catch (Exception e) { Log.d(CSU_TAG,"Exception encountered but trapped when querying table " + tablename + " Message was: \n" + e.getMessage()); Log.d(CSU_TAG,"Stacktrace was:"); e.printStackTrace(); return new MatrixCursor(new String[]{}); } } /** * Create and return a Cursor devoid of any rows and columns * Not used, prehaps of very little use. * @param db The Sqlite database in which the cursor is to be created * @return The empty Cursor */ private static Cursor getEmptyColumnLessCursor(SQLiteDatabase db) { return new MatrixCursor(new String[]{}); } /** * Write column names in the passed Cursor to the log * @param csr The Cursor to be inspected. */ public static void logCursorColumns(Cursor csr) { Log.d(CSU_TAG, new Object(){}.getClass().getEnclosingMethod().getName() + " invoked. Cursor has the following " + Integer.toString(csr.getColumnCount())+ " columns."); int position = 0; for (String column: csr.getColumnNames()) { position++; Log.d(CSU_TAG,"Column Name " + Integer.toString(position) + " is " + column ); } } /** * Write the contents of the Cursor to the log * @param csr The Cursor that is to be displayed in the log */ public static void logCursorData(Cursor csr) { int columncount = csr.getColumnCount(); int rowcount = csr.getCount(); int csrpos = csr.getPosition(); //<<< added 20171016 Log.d(CSU_TAG, new Object(){}.getClass().getEnclosingMethod().getName() + " Cursor has " + Integer.toString(rowcount) + " rows with " + Integer.toString(columncount) + " columns." ); csr.moveToPosition(-1); //Ensure that all rows are retrieved <<< added 20171016 while (csr.moveToNext()) { String unobtainable = "unobtainable!"; String logstr = "Information for row " + Integer.toString(csr.getPosition() + 1) + " offset=" + Integer.toString(csr.getPosition()); for (int i=0; i < columncount;i++) { logstr = logstr + "\n\tFor Column " + csr.getColumnName(i); switch (csr.getType(i)) { case Cursor.FIELD_TYPE_NULL: logstr = logstr + " Type is NULL"; break; case Cursor.FIELD_TYPE_FLOAT: logstr = logstr + "Type is FLOAT"; break; case Cursor.FIELD_TYPE_INTEGER: logstr = logstr + " Type is INTEGER"; break; case Cursor.FIELD_TYPE_STRING: logstr = logstr + " Type is STRING"; break; case Cursor.FIELD_TYPE_BLOB: logstr = logstr + " Type is BLOB"; break; } String strval_log = " value as String is "; String lngval_log = " value as long is "; String dblval_log = " value as double is "; String blbval_log = ""; try { strval_log = strval_log + csr.getString(i); lngval_log = lngval_log + csr.getLong(i); dblval_log = dblval_log + csr.getDouble(i); } catch (Exception e) { strval_log = strval_log + unobtainable; lngval_log = lngval_log + unobtainable; dblval_log = dblval_log + unobtainable; try { blbval_log = " value as blob is " + getBytedata(csr.getBlob(i),24); } catch (Exception e2) { e2.printStackTrace(); } } logstr = logstr + strval_log + lngval_log + dblval_log + blbval_log; } Log.d(CSU_TAG,logstr); } csr.moveToPosition(csrpos); // restore cursor position <<< added 20171016 } /** * Return a hex string of the given byte array * @param bytes The byte array to be converted to a hexadecimal string * @param limit the maximum number of bytes; * note returned string will be up to twice as long * @return The byte array represented as a hexadecimal string */ private static String getBytedata(byte[] bytes, int limit) { if (bytes.length < limit) { return convertBytesToHex(bytes); } else { byte[] subset = new byte[limit]; System.arraycopy(bytes,0,subset,0,limit); return convertBytesToHex(subset); } } // HEX characters as a char array for use by convertBytesToHex private final static char[] hexarray = "0123456789ABCDEF".toCharArray(); /** * Return a hexadecimal string representation of the passed byte array * @param bytes The byte array to be represented. * @return The string representing the byte array as hexadecimal */ private static String convertBytesToHex(byte[] bytes) { char[] hexstr = new char[bytes.length * 2]; for (int i=0; i < bytes.length; i++) { int h = bytes[i] & 0xFF; hexstr[i * 2] = hexarray[h >>> 4]; hexstr[i * 2 + 1] = hexarray[h & 0xF]; } return new String(hexstr); } }
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