IT. Expert System.


PDO and SQL 4D

SQL acceptable by 4D

(No version information available, might only be in Git)

SQL acceptable by 4DPDO and SQL 4D


4D implements strictly the ANSI 89 standard, and have it enforced. It is highly recommended to read the 4D SQL documentation to learn about the available commands. The URL of the manual is : » Below is a list of 4D SQL characteristics: it is not exhaustive, but may serve as an introduction.

Characteristics of 4D SQL
Characteristics Alternative Note
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.


Android Reference

Java basics

Java Enterprise Edition (EE)

Java Standard Edition (SE)





Java Script








Design patterns

RFC (standard status)

RFC (proposed standard status)

RFC (draft standard status)

RFC (informational status)

RFC (experimental status)

RFC (best current practice status)

RFC (historic status)

RFC (unknown status)

IT dictionary

All information of this service is derived from the free sources and is provided solely in the form of quotations. This service provides information and interfaces solely for the familiarization (not ownership) and under the "as is" condition.
Copyright 2016 © ELTASK.COM. All rights reserved.
Site is optimized for mobile devices.
Downloads: 328 / 158733357. Delta: 0.03154 с