| Index: third_party/sqlite/ext/rtree/README
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| ===================================================================
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| --- third_party/sqlite/ext/rtree/README (revision 56608)
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| +++ third_party/sqlite/ext/rtree/README (working copy)
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| @@ -1,120 +0,0 @@
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| -
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| -This directory contains an SQLite extension that implements a virtual
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| -table type that allows users to create, query and manipulate r-tree[1]
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| -data structures inside of SQLite databases. Users create, populate
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| -and query r-tree structures using ordinary SQL statements.
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| -
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| - 1. SQL Interface
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| -
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| - 1.1 Table Creation
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| - 1.2 Data Manipulation
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| - 1.3 Data Querying
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| - 1.4 Introspection and Analysis
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| -
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| - 2. Compilation and Deployment
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| -
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| - 3. References
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| -
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| -
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| -1. SQL INTERFACE
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| -
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| - 1.1 Table Creation.
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| -
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| - All r-tree virtual tables have an odd number of columns between
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| - 3 and 11. Unlike regular SQLite tables, r-tree tables are strongly
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| - typed.
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| -
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| - The leftmost column is always the pimary key and contains 64-bit
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| - integer values. Each subsequent column contains a 32-bit real
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| - value. For each pair of real values, the first (leftmost) must be
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| - less than or equal to the second. R-tree tables may be
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| - constructed using the following syntax:
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| -
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| - CREATE VIRTUAL TABLE <name> USING rtree(<column-names>)
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| -
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| - For example:
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| -
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| - CREATE VIRTUAL TABLE boxes USING rtree(boxno, xmin, xmax, ymin, ymax);
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| - INSERT INTO boxes VALUES(1, 1.0, 3.0, 2.0, 4.0);
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| -
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| - Constructing a virtual r-tree table <name> creates the following three
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| - real tables in the database to store the data structure:
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| -
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| - <name>_node
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| - <name>_rowid
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| - <name>_parent
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| -
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| - Dropping or modifying the contents of these tables directly will
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| - corrupt the r-tree structure. To delete an r-tree from a database,
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| - use a regular DROP TABLE statement:
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| -
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| - DROP TABLE <name>;
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| -
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| - Dropping the main r-tree table automatically drops the automatically
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| - created tables.
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| -
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| - 1.2 Data Manipulation (INSERT, UPDATE, DELETE).
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| -
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| - The usual INSERT, UPDATE or DELETE syntax is used to manipulate data
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| - stored in an r-tree table. Please note the following:
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| -
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| - * Inserting a NULL value into the primary key column has the
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| - same effect as inserting a NULL into an INTEGER PRIMARY KEY
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| - column of a regular table. The system automatically assigns
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| - an unused integer key value to the new record. Usually, this
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| - is one greater than the largest primary key value currently
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| - present in the table.
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| -
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| - * Attempting to insert a duplicate primary key value fails with
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| - an SQLITE_CONSTRAINT error.
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| -
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| - * Attempting to insert or modify a record such that the value
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| - stored in the (N*2)th column is greater than that stored in
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| - the (N*2+1)th column fails with an SQLITE_CONSTRAINT error.
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| -
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| - * When a record is inserted, values are always converted to
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| - the required type (64-bit integer or 32-bit real) as if they
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| - were part of an SQL CAST expression. Non-numeric strings are
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| - converted to zero.
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| -
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| - 1.3 Queries.
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| -
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| - R-tree tables may be queried using all of the same SQL syntax supported
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| - by regular tables. However, some query patterns are more efficient
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| - than others.
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| -
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| - R-trees support fast lookup by primary key value (O(logN), like
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| - regular tables).
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| -
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| - Any combination of equality and range (<, <=, >, >=) constraints
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| - on spatial data columns may be used to optimize other queries. This
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| - is the key advantage to using r-tree tables instead of creating
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| - indices on regular tables.
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| -
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| - 1.4 Introspection and Analysis.
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| -
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| - TODO: Describe rtreenode() and rtreedepth() functions.
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| -
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| -
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| -2. COMPILATION AND USAGE
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| -
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| - The easiest way to compile and use the RTREE extension is to build
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| - and use it as a dynamically loadable SQLite extension. To do this
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| - using gcc on *nix:
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| -
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| - gcc -shared rtree.c -o libSqliteRtree.so
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| -
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| - You may need to add "-I" flags so that gcc can find sqlite3ext.h
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| - and sqlite3.h. The resulting shared lib, libSqliteRtree.so, may be
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| - loaded into sqlite in the same way as any other dynamicly loadable
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| - extension.
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| -
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| -
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| -3. REFERENCES
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| -
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| - [1] Atonin Guttman, "R-trees - A Dynamic Index Structure For Spatial
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| - Searching", University of California Berkeley, 1984.
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| -
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| - [2] Norbert Beckmann, Hans-Peter Kriegel, Ralf Schneider, Bernhard Seeger,
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| - "The R*-tree: An Efficient and Robust Access Method for Points and
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| - Rectangles", Universitaet Bremen, 1990.
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