Issue #2213 - PostgreSQL: Strict typing requires explicit type casts #2234

homedirectory · 2024-04-12T09:17:58Z

Resolve #2213

Summary of changes:

Specific SQL transformations for PostgreSQL as described in the issue.
Intermediate EQL transformation now receive not only the runtime DB version but whole domain metadata.
General improvements to intermediate EQL data structures: runtime assertions, increased immutability, improved readability, reduced usage of nulls.
Documentation of various EQL components.
Some changes and enhancements to StreamUtils, requires tg-libs to be recompiled.

…tation

A canonical representation serves as a reference, thus it is written in a human-readable form.

This also includes complex ones, such as caseWhen.

…son and quantified

…s declaring multiple parameters

… resulting parse tree is more manageable

Introduce a separate rule for "like" operators and replace inheritance relationship by alternation between quantified and comparison operators.

…building it This gives us more control over the BNF representation which will assist with the transformation into ANTLR grammar format (among other ones).

This is to avoid 2 placeholder types from different contexts being accidentally considered equal.

- Add documentation - Implement toString() methods to facilitate reasoning - Reduce visibility of PropType constructor (static method should be used)

…ions This is achieved by casting the NULL to the type of the other operand

In general, this approach of asserting that an exception is thrown is far from the best because it ignores potential exceptions that may be thrown for unexpected reasons. Being more specific and expecting only a certain type of exceptions doesn't work either since the exception gets rethrown at some higher level, effectively becoming a cause of another exception. Should we be making assertions about the stack trace at this point? I don't think so.

The converstion itself was also slightly modified: * Use an unbounded VARCHAR by default instead of setting the limit to 255 chars, which has no clear basis. * Optimise for Integers by limiting the VARCHAR length to 10 chars.

…tility

And for all DB back-ends, not just PostgreSQL and SQL Server.

… with string type Wheels of EQL3 are turning so the workaround is no longer needed. Moreover, we can now be confident that the null type is never taken for the string type by mistake, which is vastly important for PostgreSQL.

…iling

* Use a sealed interface with inner classes to facilitate pattern matching with switch. * Instead of inserting type casts conditionally, depending on the database, always insert them. The conditional approach likely relied on implicit type conversion performed by some DBs. Although, endAsInt() worked correctly only with H2, which had gone unnoticed as its usage has been scarce.

This assertion reports list contents in case of failure.

homedirectory added 30 commits February 12, 2024 12:27

#2178 Add grammar rules for beginExpr()/endExpr()

22267d0

#2178 Rewrite rules for logical conditions to support begin/end grouping

e636417

#2178 Implement translation from Fling BNF to human-readable represen…

a18488e

…tation

#2178 Add a canonical representation of EQL's grammar

02a4217

A canonical representation serves as a reference, thus it is written in a human-readable form.

#2178 Extract BNF-to-text transformation into a reusable component

edd4a01

#2178 Add rules for all single operands

4b2302e

This also includes complex ones, such as caseWhen.

#2178 Rules for all possible "like" operators

537ad8e

#2178 Rules for membership predicates

f87e1fb

#2178 Split operands and operators into 2 categories: regular compari…

c19b4ba

…son and quantified

#2178 Rules for single-condition, subchaining predicates

f9b6f47

#2178 Rule for an optional alias after select

229f61e

#2178 Rules for Joins

a86cf27

#2178 A rule for "group by"

ffad729

#2178 A proper rule for model variants

c16f05b

#2178 Rules for yielding

2554ae2

#2178 Simplify the Join rule

32f38cc

#2178 Complete parameterisation of tokens corresponding to EQL method…

80e63d0

…s declaring multiple parameters

#2178 Improve readability of the translated BNF

c0f5d98

#2178 Correct the rule for date diff interval function

b2e0fe3

#2178 Implement an HTML generator for the BNF

f10a6bd

#2178 Styling adjustments for generated HTML

3946040

#2178 More styling adjustments for generated HTML

383ee28

#2178 Correct the Predicate rule

769a847

#2178 Grammar cleanup

aa0ff56

#2178 Implement basic grammar verification

b73ad98

#2178 Implement BNF to ANTLR's g4 format conversion

ccf75fd

#2196 BNF to ANTLR: generate lexer rules for terminals

d649809

#2196 BNF to ANTLR: generate terminal rules in such a way so that the…

151ef6d

… resulting parse tree is more manageable

#2178 Improve semantics of comparison operators

e74509f

Introduce a separate rule for "like" operators and replace inheritance relationship by alternation between quantified and comparison operators.

#2196, #2178 Provide our own BNF representation and a fluent API for …

6f4a070

…building it This gives us more control over the BNF representation which will assist with the transformation into ANTLR grammar format (among other ones).

homedirectory added 27 commits April 5, 2024 10:48

#2213 Use unique Hibernate placeholder types instead of a singleton

e454d04

This is to avoid 2 placeholder types from different contexts being accidentally considered equal.

#2213 Various minor improvements

f896e92

- Add documentation - Implement toString() methods to facilitate reasoning - Reduce visibility of PropType constructor (static method should be used)

#2213 Never cast a yielded value to the NULL type

4554d6e

#2213 Facilitate reuse of methods that build SQL CAST expressions

9186ba9

#2213 Make NULL compatible with the other value in comparison express…

643a678

…ions This is achieved by casting the NULL to the type of the other operand

#2213 Test comparison of nulls with non-nulls in JOIN conditions

dafb82e

Add a test utility to assert optional values equality

ffc1bf4

Add a stream utility to test whether all integers in a stream are equal

4416374

Add a stream utility to construct enumerated streams

8b9a920

#2213 EQL stage 3: more runtime assertions around yields

c5c48a1

#2213 Miscellaneous improvements

8a073a1

#2213 Extract operand-to-SQL-as-string conversion into a standalone u…

ea4657a

…tility

#2213 Support all types of values in the left-hand side of LIKE

35aaebe

And for all DB back-ends, not just PostgreSQL and SQL Server.

#2213 Test LIKE in application to non-String values

d66ca0c

#2213 Prefer an informative exception over NPE

1fa0b56

#2213 Test caseWhen expressions that return nulls

a5b7f85

#2213 Require a type cast for caseWhen that returns nulls exclusively

4636dd6

#2213 Test usage of caseWhen returning only nulls without a type cast

1629bcd

#2213 Use a more precise test assertion about an illegal EQL query fa…

a6c0035

…iling

#2213 Harden the tests with more assertions

1ca6d9c

#2213 Add tests for various use cases of type casting in caseWhen

6ddd6c7

#2213 Correct the order of parameters in endAsDecimal()

93d0ebb

#2213 Use a better suited assertion for empty lists

98c65af

This assertion reports list contents in case of failure.

homedirectory requested review from 01es and nazchk April 12, 2024 09:18

Merge branch 'develop' into Issue-#2213

73f609d

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Issue #2213 - PostgreSQL: Strict typing requires explicit type casts #2234

Issue #2213 - PostgreSQL: Strict typing requires explicit type casts #2234

homedirectory commented Apr 12, 2024 •

edited

Issue #2213 - PostgreSQL: Strict typing requires explicit type casts #2234

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Issue #2213 - PostgreSQL: Strict typing requires explicit type casts #2234

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homedirectory commented Apr 12, 2024 • edited

homedirectory commented Apr 12, 2024 •

edited