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<a href="intro.html"><h2>SQLite C Interface</h2></a><h2>Extract Metadata About A Column Of A Table</h2><blockquote><pre>int sqlite3_table_column_metadata(
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sqlite3 *db, /* Connection handle */
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const char *zDbName, /* Database name or NULL */
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const char *zTableName, /* Table name */
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const char *zColumnName, /* Column name */
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char const **pzDataType, /* OUTPUT: Declared data type */
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char const **pzCollSeq, /* OUTPUT: Collation sequence name */
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int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
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int *pPrimaryKey, /* OUTPUT: True if column part of PK */
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int *pAutoinc /* OUTPUT: True if column is auto-increment */
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</pre></blockquote><p>
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This routine returns metadata about a specific column of a specific
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database table accessible using the <a href="../c3ref/sqlite3.html">database connection</a> handle
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passed as the first function argument.</p>
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<p>The column is identified by the second, third and fourth parameters to
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this function. The second parameter is either the name of the database
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(i.e. "main", "temp", or an attached database) containing the specified
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table or NULL. If it is NULL, then all attached databases are searched
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for the table using the same algorithm used by the database engine to
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resolve unqualified table references.</p>
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<p>The third and fourth parameters to this function are the table and column
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name of the desired column, respectively. Neither of these parameters
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<p>Metadata is returned by writing to the memory locations passed as the 5th
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and subsequent parameters to this function. Any of these arguments may be
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NULL, in which case the corresponding element of metadata is omitted.</p>
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<tr><th> Parameter <th> Output<br>Type <th> Description</p>
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<p><tr><td> 5th <td> const char* <td> Data type
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<tr><td> 6th <td> const char* <td> Name of default collation sequence
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<tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
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<tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
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<tr><td> 9th <td> int <td> True if column is <a href="../autoinc.html">AUTOINCREMENT</a>
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<p>The memory pointed to by the character pointers returned for the
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declaration type and collation sequence is valid only until the next
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call to any SQLite API function.</p>
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<p>If the specified table is actually a view, an <a href="../c3ref/c_abort.html">error code</a> is returned.</p>
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<p>If the specified column is "rowid", "oid" or "_rowid_" and an
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<a href="../lang_createtable.html#rowid">INTEGER PRIMARY KEY</a> column has been explicitly declared, then the output
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parameters are set for the explicitly declared column. If there is no
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explicitly declared <a href="../lang_createtable.html#rowid">INTEGER PRIMARY KEY</a> column, then the output
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parameters are set as follows:</p>
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collation sequence: "BINARY"
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<p>This function may load one or more schemas from database files. If an
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error occurs during this process, or if the requested table or column
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cannot be found, an <a href="../c3ref/c_abort.html">error code</a> is returned and an error message left
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in the <a href="../c3ref/sqlite3.html">database connection</a> (to be retrieved using sqlite3_errmsg()).</p>
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<p>This API is only available if the library was compiled with the
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<a href="../compile.html#enable_column_metadata">SQLITE_ENABLE_COLUMN_METADATA</a> C-preprocessor symbol defined.
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</p><p>See also lists of
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<a href="objlist.html">Objects</a>,
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<a href="constlist.html">Constants</a>, and
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<a href="funclist.html">Functions</a>.</p>
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