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v5:dictionary:column_attributes

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Dictionary Column Attributes

Add Argument Definitions

Description

When creating a column in a table using the dictionary methods, the information provided must confirm to the following specification. Each column created has a number of mandatory and optional parameters.


$fields is a string, not an array

Basic Syntax

The basic syntax of the attributes is as follows:

  • All the information for the column must occur on a single line.
  • The line ending may be a newline or carriage return/newline combination.
  • Each attribute must be separated by at least one tab or space.
  • The attributes must be specified in the order below
    1. Column Name
    2. Meta Attributes
    3. Optional Arguments
/*
 * Correct syntax
 */
$flds = "
COL1 C(60) NOTNULL DEFAULT 'abc',
COL2 I8 NOTNULL DEFAULT 0
";
 
/*
 * Incorrect syntax
 */
$flds = "
COL1 
C(60) 
NOTNULL 
DEFAULT 'abc',
COL2 
I8 
NOTNULL
DEFAULT 0
";

Attributes

Column Name

  • The column name must conform to any database specific standards related to naming and length.

Meta Attributes

  • The column attributes in terms of type and length must be specified in terms of ADODb metaType descriptions, not the database definition for the type.

Optional Arguments

The following optional arguments may also be assigned to the column, table or key. If the attribute is inappropriate for the operation or column type or not supported by the DBMS, it is ignored.


Usage: Column

AUTO or AUTOINCREMENT

Creates the column as auto-increment. Support for this varies from one database to another. Some databases designate a field with an auto-increment flag as the primary key.


Usage: Index

CONSTRAINT


Usage: Column

DEF or DEFAULT

DEF indicates a default value for a column when a row is created. Some databases also require a field with a default value to be designated as NOT NULL, so that is automatically added to the column string


DEFDATE


DEFTIMESTAMP


Usage: Column

ENUM

In database that support the ENUM datatype, append a parenthesized, quoted list of enum values

ENUM('lions','tigers','halibut')

INDEX


KEY


NOQUOTE


Usage: Column

NOTNULL


Usage: Index

PRIMARY


Usage: Index

UNIQUE

UNIQUE is an option against a key and indicates that duplicate values across all columns in the key are not allowed.


UNSIGNED

v5/dictionary/column_attributes.1454170453.txt.gz · Last modified: 2017/04/21 11:28 (external edit)