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<!-- keywords: SQLITE_INDEX_CONSTRAINT_EQ SQLITE_INDEX_CONSTRAINT_FUNCTION SQLITE_INDEX_CONSTRAINT_GE SQLITE_INDEX_CONSTRAINT_GLOB SQLITE_INDEX_CONSTRAINT_GT SQLITE_INDEX_CONSTRAINT_IS SQLITE_INDEX_CONSTRAINT_ISNOT SQLITE_INDEX_CONSTRAINT_ISNOTNULL SQLITE_INDEX_CONSTRAINT_ISNULL SQLITE_INDEX_CONSTRAINT_LE SQLITE_INDEX_CONSTRAINT_LIKE SQLITE_INDEX_CONSTRAINT_LIMIT SQLITE_INDEX_CONSTRAINT_LT SQLITE_INDEX_CONSTRAINT_MATCH SQLITE_INDEX_CONSTRAINT_NE SQLITE_INDEX_CONSTRAINT_OFFSET SQLITE_INDEX_CONSTRAINT_REGEXP -->
<div class=nosearch>
<a href="../c3ref/intro.html"><h2>SQLite C Interface</h2></a>
<h2>Virtual Table Constraint Operator Codes</h2>
</div>
<blockquote><pre>
#define SQLITE_INDEX_CONSTRAINT_EQ          2
#define SQLITE_INDEX_CONSTRAINT_GT          4
#define SQLITE_INDEX_CONSTRAINT_LE          8
#define SQLITE_INDEX_CONSTRAINT_LT         16
#define SQLITE_INDEX_CONSTRAINT_GE         32
#define SQLITE_INDEX_CONSTRAINT_MATCH      64
#define SQLITE_INDEX_CONSTRAINT_LIKE       65
#define SQLITE_INDEX_CONSTRAINT_GLOB       66
#define SQLITE_INDEX_CONSTRAINT_REGEXP     67
#define SQLITE_INDEX_CONSTRAINT_NE         68
#define SQLITE_INDEX_CONSTRAINT_ISNOT      69
#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL  70
#define SQLITE_INDEX_CONSTRAINT_ISNULL     71
#define SQLITE_INDEX_CONSTRAINT_IS         72
#define SQLITE_INDEX_CONSTRAINT_LIMIT      73
#define SQLITE_INDEX_CONSTRAINT_OFFSET     74
#define SQLITE_INDEX_CONSTRAINT_FUNCTION  150
</pre></blockquote>
<p>
These macros define the allowed values for the
<a href="../c3ref/index_info.html">sqlite3_index_info</a>.aConstraint[].op field.  Each value represents
an operator that is part of a constraint term in the WHERE clause of
a query that uses a <a href="../vtab.html">virtual table</a>.</p>

<p>The left-hand operand of the operator is given by the corresponding
aConstraint[].iColumn field.  An iColumn of -1 indicates the left-hand
operand is the rowid.
The SQLITE_INDEX_CONSTRAINT_LIMIT and SQLITE_INDEX_CONSTRAINT_OFFSET
operators have no left-hand operand, and so for those operators the
corresponding aConstraint[].iColumn is meaningless and should not be
used.</p>

<p>All operator values from SQLITE_INDEX_CONSTRAINT_FUNCTION through
value 255 are reserved to represent functions that are overloaded
by the <a href="../vtab.html#xfindfunction">xFindFunction method</a> of the virtual table
implementation.</p>

<p>The right-hand operands for each constraint might be accessible using
the <a href="../c3ref/vtab_rhs_value.html">sqlite3_vtab_rhs_value()</a> interface.  Usually the right-hand
operand is only available if it appears as a single constant literal
in the input SQL.  If the right-hand operand is another column or an
expression (even a constant expression) or a parameter, then the
sqlite3_vtab_rhs_value() probably will not be able to extract it.
The SQLITE_INDEX_CONSTRAINT_ISNULL and
SQLITE_INDEX_CONSTRAINT_ISNOTNULL operators have no right-hand operand
and hence calls to sqlite3_vtab_rhs_value() for those operators will
always return SQLITE_NOTFOUND.</p>

<p>The collating sequence to be used for comparison can be found using
the <a href="../c3ref/vtab_collation.html">sqlite3_vtab_collation()</a> interface.  For most real-world virtual
tables, the collating sequence of constraints does not matter (for example
because the constraints are numeric) and so the sqlite3_vtab_collation()
interface is not commonly needed.
</p><p>See also lists of
  <a href="../c3ref/objlist.html">Objects</a>,
  <a href="../c3ref/constlist.html">Constants</a>, and
  <a href="../c3ref/funclist.html">Functions</a>.</p>