[Active Record] Renamed private methods create_record and update_record

 This is to ensure that they are not accidentally called by the app code.
 They are renamed to _create_record and _update_record respectively.
 Closes #11645
add capture_sql method to compare sql statements and compare

Other methods compare specific patterns, this method outputs
the actual sql query that is generated.
add test to compare sql statements in delete_all query

delete_all sql if an association is not loaded should behave
the same as if the association is loaded. This test ensures
the SQL statements are exactly the same.
fix delete_all to remove records directly

When delete_all is run on a CollectionProxy and has a
dependency of delete_all the SQL that is produced has an IN
statement. (DELETE FROM `associated_model` where `associated_model`
.`parent_id` = 1 AND `associated_model`.`id` IN (1, 2, 3...)).
This only happens if the association is not loaded (both loaded
and non-loaded delete_all should behave the same. This is a huge
problem when it comes to deleting many records because the query
becomes very slow. Instead the SQL produced should be (DELETE FROM
`assoicated_model` where `associated_model`.`parent_model_id`=1).

I fixed this by making sure the check for loaded and destroy also
makes sure that the dependent is not delete_all, so the conditional
goes to the else and deletes the records directly without the IN
statement.
Merge pull request #14546 from eileencodes/fix_delete_all_to_not_use_IN_statement

Fix delete all to not produce sql in statement
Make AS::SafeBuffer#prepend act like String#prepend

Make `#prepend` method modify instance in-place and return self
instead of just returning modified value. That is exactly what
`#prepend!` method was doing previously, so it's deprecated from
now on.
refactor assert_sql query to reuse capture_sql

set assert_sql to reuse the capture_sql method from above
instead of repeating the code

in response to comments on issue #14546
Merge pull request #14548 from eileencodes/refactor_capture_sql_in_tests

refactor assert_sql query to reuse capture_sql
PostgreSQL determine `Column#type` through corresponding OID. #7814

I ran the whole test suite and compared the old to the new types.
Following is the list of types that did change with this patch:

```
DIFFERENT TYPE FOR mood: NEW: enum, BEFORE:
DIFFERENT TYPE FOR floatrange: NEW: floatrange, BEFORE: float
```

The `floatrange` is a custom type. The old type `float` was simply a coincidence
form the name `floatrange` and our type-guessing.
Merge pull request #14513 from senny/pg/responsible_oid

PostgreSQL determine `Column#type` through corresponding OID. #7814
PostgreSQL, register custom domains. Closes #14305.

This patch registers custom domains in our OID-type_map.
They will behave exactly as the type specified by `pg_type.typbasetype`.

/cc @matthewd
refactor, use `typtype` instead of `typinput` to segment PG types.
fix, adjust OID query without range support to include required fields.

This is a follow-up fix to f7a6b115fea9f675190a79b701c7034214678f19 and
06082f66d541e581110406bbac3bc395bace3f86
Clarify 'database does not exist' message and implementation.

* Clarify what the situation is and what to do.
* Advise loading schema using `rake db:setup` instead of migrating.
* Use a rescue in the initializer rather than extending the error
  message in-place.
* Preserve the original backtrace of other errors by using `raise`
  rather than raising again with `raise error`.

References 0ec45cd15d0a2f5aebc75e23d841b6c12f3ba763
only ask if `t` is empty once.
do not create memo objects since we'll just throw them away
combine move_regexp and move_string so we only loop over states once
push move_string in to `move`
Merge branch 'rmc'

* rmc:
  push move_string in to `move`
  combine move_regexp and move_string so we only loop over states once
  do not create memo objects since we'll just throw them away
  only ask if `t` is empty once.
Changed 'so' to 'see'