| INTEGER |
Modify the SQL to use INT. |
INT is the supported integer type in 4Dv12.0. |
| CHAR |
Use VARCHAR instead. |
Unsupported in 4Dv12.0 |
| UNION |
Unsupported. Make separate queries. |
Unsupported in 4Dv12.0 |
| SELECT 1 + 1; |
SELECT 1 + 1 FROM _USER_SCHEMAS; |
FROM is required |
| FLOAT |
Cast the FLOAT value into a FLOAT or STRING, with an SQL 4D function (CAST, ROUND, TRUNC or TRUNCATE) |
Unsupported in current versions of the PDO_4D driver |
| Strong typing |
Take care your SQL query, or your PHP code provides data with the expected type |
One must provide the right type that 4D expect. One can't insert '1' (as a string) in an INTEGER column.
|
| PDO::execute($row)() : only works if all the table's column are of type TEXT or VARCHAR |
Use the prepared statements, and use the right types. |
The PDO extension cast all values through execute() as string, and expect the SQL database to parse the values. |
| SELECT NULL FROM TABLE |
Do not use NULL constants. Extract them from the table |
It is not allowed to use the NULL constant in the select list |
| SELECT * FROM TABLE WHERE 1 |
Use WHERE 1 = 1 |
A constant can't be used in a WHERE clause |
| SHOW TABLES |
Use system tables |
The list of tables, schemas, index, etc. are in these system tables :
_USER_TABLES, _USER_COLUMNS,
_USER_INDEXES, _USER_CONSTRAINTS,
_USER_IND_COLUMNS, _USER_CONS_COLUMNS,
and _USER_SCHEMAS.
|
| SQL structure delimiter |
Use the following function to protect SQL elements:
function sqlEscapeElement(elem) {
return '[' . str_replace(']',']]', $elem) . ']';
}
|
To escape SQL elements names (tables, fields, users,
groups, schema, primary key, etc.), the whole identifier
must be between square brackets, and the closing
brackets ']' must be doubled.
|