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for file in `ack -i '\bA\s+SQL' -l`; do perl -i -pe 's/\b(a)(\s+SQL)/\1n\2/gi' $file; done git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@300101 c90b9560-bf6c-de11-be94-00142212c4b1
132 lines
4.5 KiB
XML
132 lines
4.5 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<refentry xml:id="ref.pdo-4d.sql4d" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
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<refnamediv>
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<refname>SQL acceptable by 4D</refname>
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<refpurpose>PDO and SQL 4D</refpurpose>
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</refnamediv>
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<refsect1 role="description">
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&reftitle.description;
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<para>
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4D implements strictly the ANSI 89 standard, and have it enforced.
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It is highly recommended to read the 4D SQL documentation to learn
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about the available commands. The URL of the manual is :
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<link xlink:href="&url.4d.doc;">&url.4d.doc;</link>.
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Below is a list of 4D SQL characteristics: it is not exhaustive,
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but may serve as an introduction.
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</para>
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<para>
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<table>
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<title>Characteristics of 4D SQL</title>
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<tgroup cols="3">
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<thead>
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<row>
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<entry>Characteristics</entry>
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<entry>Alternative</entry>
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<entry>Note</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry>INTEGER</entry>
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<entry>Modify the SQL to use INT.</entry>
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<entry>INT is the supported integer type in 4Dv12.0.</entry>
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</row>
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<row>
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<entry>CHAR</entry>
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<entry>Use VARCHAR instead.</entry>
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<entry>Unsupported in 4Dv12.0</entry>
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</row>
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<row>
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<entry>UNION</entry>
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<entry>Unsupported. Make separate queries.</entry>
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<entry>Unsupported in 4Dv12.0</entry>
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</row>
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<row>
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<entry>SELECT 1 + 1;</entry>
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<entry>SELECT 1 + 1 FROM _USER_SCHEMAS;</entry>
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<entry>FROM is required</entry>
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</row>
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<row>
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<entry>FLOAT</entry>
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<entry>Cast the FLOAT value into a FLOAT or STRING, with an SQL 4D function (CAST, ROUND, TRUNC or TRUNCATE)</entry>
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<entry>Unsupported in current versions of the PDO_4D driver</entry>
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</row>
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<row>
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<entry>Strong typing</entry>
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<entry>Take care your SQL query, or your PHP code provides data with the expected type</entry>
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<entry>
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One must provide the right type that 4D expect. One can't insert '1' (as a string) in an INTEGER column.
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</entry>
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</row>
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<row>
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<entry><function>PDO::execute($row)</function> : only works if all the table's column are of type TEXT or VARCHAR</entry>
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<entry>Use the prepared statements, and use the right types.</entry>
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<entry>The PDO extension cast all values through execute() as string, and expect the SQL database to parse the values.</entry>
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</row>
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<row>
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<entry>SELECT NULL FROM TABLE</entry>
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<entry>Do not use NULL constants. Extract them from the table</entry>
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<entry>It is not allowed to use the NULL constant in the select list</entry>
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</row>
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<row>
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<entry>SELECT * FROM TABLE WHERE 1</entry>
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<entry>Use WHERE 1 = 1</entry>
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<entry>A constant can't be used in a WHERE clause</entry>
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</row>
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<row>
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<entry>SHOW TABLES</entry>
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<entry>Use system tables</entry>
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<entry>
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The list of tables, schemas, index, etc. are in these system tables :
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<literal>_USER_TABLES</literal>, <literal>_USER_COLUMNS</literal>,
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<literal>_USER_INDEXES</literal>, <literal>_USER_CONSTRAINTS</literal>,
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<literal>_USER_IND_COLUMNS</literal>, <literal>_USER_CONS_COLUMNS</literal>,
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and <literal>_USER_SCHEMAS</literal>.
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</entry>
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</row>
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<row>
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<entry>SQL structure delimiter</entry>
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<entry>
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Use the following function to protect SQL elements:
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function sqlEscapeElement(elem) {
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return '[' . str_replace(']',']]', $elem) . ']';
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}
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</entry>
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<entry>
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To escape SQL elements names (tables, fields, users,
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groups, schema, primary key, etc.), the whole identifier
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must be between square brackets, and the closing
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brackets ']' must be doubled.
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</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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</para>
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</refsect1>
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</refentry>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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indent-tabs-mode:nil
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sgml-parent-document:nil
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sgml-default-dtd-file:"~/.phpdoc/manual.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:nil
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sgml-local-ecat-files:nil
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End:
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vim600: syn=xml fen fdm=syntax fdl=2 si
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vim: et tw=78 syn=sgml
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vi: ts=1 sw=1
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-->
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