[QGIS Commit] r11952 - in docs/trunk/english_us/user_guide: .
material_wonder
svn_qgis at osgeo.org
svn_qgis at osgeo.org
Sat Nov 7 08:58:46 EST 2009
Author: dassau
Date: 2009-11-07 08:58:45 -0500 (Sat, 07 Nov 2009)
New Revision: 11952
Modified:
docs/trunk/english_us/user_guide/material_wonder/user.odt
docs/trunk/english_us/user_guide/working_with_vector.tex
Log:
- extended query builder description
Modified: docs/trunk/english_us/user_guide/material_wonder/user.odt
===================================================================
(Binary files differ)
Modified: docs/trunk/english_us/user_guide/working_with_vector.tex
===================================================================
--- docs/trunk/english_us/user_guide/working_with_vector.tex 2009-11-07 12:54:56 UTC (rev 11951)
+++ docs/trunk/english_us/user_guide/working_with_vector.tex 2009-11-07 13:58:45 UTC (rev 11952)
@@ -1580,14 +1580,18 @@
\subsection{Query Builder}\label{sec:query_builder}
\index{Query Builder}
-The Query Builder allows you to define a subset of a table and display
-it as a layer in QGIS. It can currently only be used with PostGIS layers.
-For example, if you have a \filename{towns} layer with a
-\usertext{population} field you could select only larger towns by entering
+The \button{Advanced search\dots} button opens the Query Builder and allows you to
+define a subset of a table using a SQL-like WHERE clause, display the result in the
+main window and save it as a Shapefile. For example, if you have a
+\filename{towns} layer
+with a \usertext{population} field you could select only larger towns by entering
\usertext{population > 100000} in the SQL box of the query builder. Figure
\ref{fig:query_builder} shows an example of the query builder populated with
data from a PostGIS layer with attributes stored in PostgreSQL.
+The Fields, Values and Operators sections help the user to construct the SQL-like
+WHERE clause easily in the text field SQL where clause window.
+
\begin{figure}[ht]
\begin{center}
\caption{Query Builder \nixcaption}\label{fig:query_builder}\smallskip
@@ -1595,21 +1599,31 @@
\end{center}
\end{figure}
-The query builder\index{Query Builder} lists the layer's database
-fields in the list box on the left. You can get a sample of the data
-contained in the highlighted field by clicking on the \button{Sample} button\index{Query
-Builder!generating sample list}. This retrieves the first 25 distinct values
-for the field from the database. To get a list of all possible values for a
-field, click on the \button{All} button\index{Query Builder!getting all
-values}. To add a selected field or value to the query, double-click on
-it\index{Query Builder!adding fields}. You can use the various buttons to
-construct the query or you can just type it into the SQL box.
+The \textbf{Fields list} contains all attributes of the attribute table to be
+searched. To add an attribute to the SQL where clause field, double click its
+name in the Fields list. Generally you can use the various fields, values and
+operators to construct the query or you can just type it into the SQL box.
-To test a query, click on the \button{Test} button\index{Query Builder!testing
-queries}. This will return a count of the number of records that will be
-included in the layer. When satisfied with the query, click \button{OK}. The
-SQL for the where clause will be shown in the SQL column of the layer list.
+The \textbf{Values list} lists the values of an attribute. To list all possible
+values of an attribute, select the attribute in the Fields list and click the
+\button{All} button\index{Query Builder!getting all values}. To list all values
+of an attribute that are present in the sample table, select the attribute in
+the Fields list and click the \button{Sample}
+button\index{Query Builder!generating sample list}. To add a value to the SQL
+where clause field, double click its name in the Values list.
+The \textbf{Operators section} contains all usable operators. To add an operator
+to the SQL where clause field, click the appropriate button. Relational operators
+( = , > , \dots), string comparison operator ( LIKE ), logical operators ( AND , OR
+, \dots) are available.
+
+The \button{Clear} button clears the text in the SQL where clause text field. The
+\button{Test} button shows a message box with the number of features satisfying
+the current query, which is usable in the process of query construction. The
+\button{OK} button closes the window and selects the features satisfying the
+query. The \button{Cancel} button closes the window without changing the current
+selection.
+
\begin{Tip}\caption{\textsc{Changing the Layer Definition}}\index{Query
Builder!changing layer definitions}
\qgistip{You can change the layer definition after it is loaded by altering
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