* DB2 exists - use existsWithCaseWhen true, similar to #3849
Fixes exists() query regression with DB2 by using the platform flag existsWithCaseWhen = true;
* DB2 using existsFromClause = " from sysibm.sysdummy1";
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Co-authored-by: robin.bygrave <robin.bygrave@eroad.com>
* #3848 Fix regression for Sql Server and Oracle with exists() introduced in 18.2.0
Fix#3848: exists() generates invalid scalar SQL on SQL Server and Oracle
Query.exists() generated `select exists(<subquery>)`, which is valid on
Postgres/H2/MySQL but rejected by SQL Server and Oracle since both only
support EXISTS as a predicate, not as a directly selectable scalar boolean
expression. ┃
┃
Add DatabasePlatform.existsWithCaseWhen/existsFromClause capability flags
and use them in CQueryBuilder.wrapSelectExists() to generate
`select case when exists(<subquery>) then 1 else 0 end` on platforms that ┃
need it, with an additional ` from dual` suffix for Oracle (which requires ┃
a FROM clause on every select). CQueryExists reads the boolean result via ┃
ResultSet.getBoolean(1), which correctly interprets the resulting 0/1 int.
* Fix tests TestInsertCheckUnique for Oracle and SQL Server
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Co-authored-by: robin.bygrave <robin.bygrave@eroad.com>
* Use autocommit false with findIterate for Postgres
* Use autocommit false with findIterate for Postgres
* Use autocommit false with FindDto queries for Postgres
* Use autocommit false with SqlQuery findIterate queries for Postgres
* Ensure that TransactionFactory.createReadOnlyTransaction() returns an ImplicitReadOnlyTransaction
This change changes TransactionFactoryTenant.createReadOnlyTransaction() to return a ImplicitReadOnlyTransaction, as that is now used to support Postgres use of cursors with findIterate style queries.
* #3552 Column alias required for SQL Server + findCount + distinct
- Modifies CQueryBuilder with the main fix which is to use the database platform selectCountWithColumnAlias for all distinct queries [and later disable it for single column case]
- Modifies SqlTreeBuilder because we need to NOT use the column alias for the count distinct SINGLE COLUMN case. So change here to:
- build the root SqlTreeNode first as part of constructor
- use rootNode.isSingleProperty() to NOT use column alias for the single column case
- Hence need to initialise DefaultDbSqlContext AFTER the root SqlTreeNode
- Modifies DefaultDbSqlContext with no effective change, just columnIndex++ ONLY when we are actually using column alias
- Modifies H2Platform to also use selectCountWithColumnAlias true
* #3552 selectCountWithColumnAlias true for MariaDB and MySql
Plus fix TestRowCount for Oracle platform
Rob Bygrave