Java SQLiteStatement.simpleQueryForLong方法代码示例

import net.sqlcipher.database.SQLiteStatement; //导入方法依赖的package包/类
/**
 * Perform an internal string-to-integer lookup using the compiled
 * {@link SQLiteStatement} provided. If a mapping isn't found in database, it will be
 * created. All new, uncached answers are added to the cache automatically.
 *
 * @param query Compiled statement used to query for the mapping.
 * @param insert Compiled statement used to insert a new mapping when no
 *            existing one is found in cache or from query.
 * @param value Value to find mapping for.
 * @param cache In-memory cache of previous answers.
 * @return An unique integer mapping for the given value.
 */
private long lookupAndCacheId(SQLiteStatement query, SQLiteStatement insert, String value, HashMap<String, Long> cache) {
    long id = -1;
    try {
        // Try searching database for mapping
        DatabaseUtils.bindObjectToProgram(query, 1, value);
        id = query.simpleQueryForLong();
    } catch (SQLiteDoneException e) {
        // Nothing found, so try inserting new mapping
        DatabaseUtils.bindObjectToProgram(insert, 1, value);
        id = insert.executeInsert();
    }
    if (id != -1) {
        // Cache and return the new answer
        cache.put(value, id);
        return id;
    } else {
        // Otherwise throw if no mapping found or created
        throw new IllegalStateException("Couldn't find or create internal lookup table entry for value " + value);
    }
}
 

import net.sqlcipher.database.SQLiteStatement; //导入方法依赖的package包/类
protected SqlStorageIterator<T> getIndexSpanningIteratorOrNull(SQLiteDatabase db, boolean includeData) {
    //If we're just iterating over ID's, we may want to use a different, much
    //faster method depending on our stats. This method retrieves the
    //index records that _don't_ exist so we can assume the spans that
    //do.
    if (!includeData && STORAGE_OPTIMIZATIONS_ACTIVE) {

        SQLiteStatement min = db.compileStatement("SELECT MIN(" + DatabaseHelper.ID_COL + ") from " + table);

        SQLiteStatement max = db.compileStatement("SELECT MAX(" + DatabaseHelper.ID_COL + ") from " + table);

        SQLiteStatement count = db.compileStatement("SELECT COUNT(" + DatabaseHelper.ID_COL + ") from " + table);

        int minValue = (int)min.simpleQueryForLong();
        int maxValue = (int)max.simpleQueryForLong() + 1;
        int countValue = (int)count.simpleQueryForLong();

        min.close();
        max.close();
        count.close();

        double density = countValue / (maxValue - minValue * 1.0);

        //Ok, so basic metrics:
        //1) Only use a covering iterator if the number of records is > 1k
        //2) Only use a covering iterator if the number of records is less than 100k (vital, hard limit)
        //3) Only use a covering iterator if the record density is 50% or more
        if (countValue > 1000 &&
                countValue < 100000 &&
                density >= 0.5) {
            return getCoveringIndexIterator(db, minValue, maxValue, countValue);
        }
    }
    return null;
}
 

import net.sqlcipher.database.SQLiteStatement; //导入方法依赖的package包/类
/**
 * Utility method to run the query on the db and return the value in the
 * first column of the first row.
 */
public static long longForQuery(SQLiteDatabase db, String query) {
    SQLiteStatement prog = db.compileStatement(query);
    try {
        return prog.simpleQueryForLong();
    } finally {
        prog.close();
    }
}
 

import net.sqlcipher.database.SQLiteStatement; //导入方法依赖的package包/类
/**
 * Utility method to run the pre-compiled query and return the value in the
 * first column of the first row.
 */
public static long longForQuery(SQLiteStatement prog, String[] selectionArgs) {
    if (selectionArgs != null) {
        int size = selectionArgs.length;
        for (int i = 0; i < size; i++) {
            bindObjectToProgram(prog, i + 1, selectionArgs[i]);
        }
    }
    long value = prog.simpleQueryForLong();
    return value;
}
 

import net.sqlcipher.database.SQLiteStatement; //导入方法依赖的package包/类
public long queryForLong(String statement) throws SQLException {
	SQLiteStatement stmt = null;
	try {
		stmt = db.compileStatement(statement);
		long result = stmt.simpleQueryForLong();
		logger.trace("{}: query for long simple query returned {}: {}", this, result, statement);
		return result;
	} catch (android.database.SQLException e) {
		throw SqlExceptionUtil.create("queryForLong from database failed: " + statement, e);
	} finally {
		if (stmt != null) {
			stmt.close();
		}
	}
}