| Platform SDK: Active Directory, ADSI, and Directory Services |
A query filter is simply the act of telling Active Directory what you want to find — in LDAP query syntax. All the specified data access technologies listed in the Choosing the Data Access Technology topic support the LDAP query syntax.
The LDAP query syntax is the following:
<expression><expression>…
A filter can contain one or more expressions. An expression has the following form:
(<logicaloperator><comparison><comparison…>)
where <logicaloperator> is the following:
| Logical operator | Meaning |
|---|---|
| | | OR |
| & | AND |
| ! | NOT |
and <comparison> is the following:
(<attribute><operator><value>)
where <attribute> is the lDAPDisplayName of the attribute to evaluate, <value> is the value to compare against, and <operator> is one of the following comparison operators:
| Logical operator | Meaning |
|---|---|
| = | Equals |
| ~= | Approximately equals |
| <= | Less than or equal to |
| >= | Greater than or equal to |
In addition, depending on the attribute syntax, the <value> may contain the * wildcard. Note that a <value> containing only * checks for the existence of the <attribute>.