Issue #2990118 by amateescu: Optimize 'initial' and 'initial_from_field' handling in MySQL and PostgreSQL

(cherry picked from commit bc328489)

Issue #2616724 by amateescu, daffie: Warn when trying to create a database table with a NOT NULL => FALSE primary key

Issue #2976493 by tstoeckler, daffie: Creating a table with an explicitly empty primary key is broken on PostgreSQL

Issue #2881522 by mondrake, tstoeckler, daffie, alexpott, amateescu, catch: Add a Schema::findPrimaryKeyColumns method to remove database specific logic from test

Issue #2849669 by alexpott, pwolanin, Munavijayalakshmi, dawehner: Fix \Drupal\Component\Utility\Unicode() because of the Symfony mbstring polyfill

Issue #2951242 by alexpott, amateescu, bmunslow, Berdir, greg606, donaldp: Allow BaseFieldDefinition::setInitialValueFromField() to set a default value - this fixes issues with block_content_update_8400()

Issue #2903908 by mfernea, martin107: Fix 'Drupal.Commenting.FunctionComment.ParamCommentIndentation' coding standard

Issue #2615496 by amateescu, joseph.olstad, amcgowanca, alexpott, Fabianx, djdevin, greggles, tstoeckler: A serial/primary key field can not be added to an existing table

Issue #2854529 by alexpott, xjm, klausi, Chi, Mixologic: Fix Drupal.Scope.MethodScope - all methods should have scopes

Issue #2776975 by joelpittet, dawehner, tim.plunkett, xjm, pfrenssen: March 3, 2017: Convert core to array syntax coding standards for Drupal 8.3.x RC phase

Issue #1079762 by mradcliffe, bzrudi71, alexpott, daffie, ogi: DatabaseSchema_pgsql::queryTableInformation() is slow

Revert "Issue #1079762 by mradcliffe, bzrudi71: DatabaseSchema_pgsql::queryTableInformation() is slow"

This reverts commit 868639ce.

Issue #2791375 by shashikant_chauhan: Fix $tableInformation documentation in pgsql and mysql schema.php

Issue #2777451 by markdorison, er.pushpinderrana, alexpott: @see references not forming links in documentation

Issue #2753475 by amateescu, timmillwood: Support using the values of another field as initial values when adding a new field

Issue #2719695 by alexpott, Mile23: Fix 'Drupal.Classes.ClassDeclaration.CloseBraceAfterBody' coding standard

Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

(cherry picked from commit e0516e39)

Issue #2594845 by er.manojsharma, tarekdj, snehi, dpopdan, anil280988, jhodgdon, cilefen: Many database driver classes have no class doc blocks

Issue #1031122 by alexpott, greg.1.anderson, catch, sun, stefan.r, pwolanin: postgres changeField() is unable to convert to bytea column type correctly

Issue #2561129 by plach, alexpott, catch: Composite indexes are not correctly deleted/re-created when updating a field storage definition

This reverts commit f3040e71.

Issue #2537928 by stefan.r, dawehner, alexpott, webflo, jhedstrom: MySQL index normalization only works on table create

Issue #2477413 by daffie, Crell, bzrudi71, stefan.r, catch, mradcliffe, chx: Increase minimum version requirement for Postgres to 9.1.2

Issue #1392754 by tss, justAChris, jhodgdon: Comply with new documentation standards for @file for namespaced class files

Issue #1923406 by stefan.r, yannickoo, catch, Crell, amateescu, pwolanin, morgantocker, Damien Tournoud, sun: Use ASCII character set on alphanumeric fields so we can index all 255 characters

Revert "Issue #1923406 by stefan.r, yannickoo: Use ASCII character set on alphanumeric fields so we can index all 255 characters"

This reverts commit ac4e35ce.

Issue #1923406 by stefan.r, yannickoo: Use ASCII character set on alphanumeric fields so we can index all 255 characters

Issue #1668644 by Island Usurper, phayes, daffie, Brandonian, gease: PostgreSQL: Impossible to change a field to serial, bigserial, or numeric