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Add FullTextTable class attribute & FullTextIndexed property attribute for easy FTS indexing #1294

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Add FullTextTable class attribute & FullTextIndexed property attribute for easy FTS indexing #1294

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136 changes: 135 additions & 1 deletion src/SQLite.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -833,8 +833,31 @@ public int DropTable<
/// </param>
public int DropTable (TableMapping map)
{
var count = 0;

if (map.FullTextTableName != null && map.FullTextColumns.Length > 0) {
// Drop full text index before content table
var queryFullText = string.Format ("DROP TABLE IF EXISTS \"{0}\"", map.FullTextTableName);
count += Execute (queryFullText);

// Drop full text index triggers
var queryFullTextTriggerBeforeUpdate = string.Format ("DROP TRIGGER IF EXISTS \"{0}_t_bu\"", map.FullTextTableName);
count += Execute (queryFullTextTriggerBeforeUpdate);

var queryFullTextTriggerBeforeDelete = string.Format ("DROP TRIGGER IF EXISTS \"{0}_t_bd\"", map.FullTextTableName);
count += Execute (queryFullTextTriggerBeforeDelete);

var queryFullTextTriggerAfterUpdate = string.Format ("DROP TRIGGER IF EXISTS \"{0}_t_au\"", map.FullTextTableName);
count += Execute (queryFullTextTriggerAfterUpdate);

var queryFullTextTriggerAfterInsert = string.Format ("DROP TRIGGER IF EXISTS \"{0}_t_ai\"", map.FullTextTableName);
count += Execute (queryFullTextTriggerAfterInsert);
}

var query = string.Format ("drop table if exists \"{0}\"", map.TableName);
return Execute (query);
count += Execute (query);

return count;
}

/// <summary>
Expand Down Expand Up @@ -941,6 +964,39 @@ public CreateTableResult CreateTable (
CreateIndex (indexName, index.TableName, columns, index.Unique);
}

// Create full text indexes
if (map.FullTextTableName != null) {
if (map.FullTextColumns.Length == 0) {
throw new Exception ("Must have at least one full text index column to specify a full text index for the table");
}

var fullTextColsNames = map.FullTextColumns.Select (c => c.Name);
// Only support FTS4 because content= options to link an FTS table to external tables is not supported in FTS3
var queryFullText = "CREATE VIRTUAL TABLE IF NOT EXISTS \"" + map.FullTextTableName + "\" USING fts4(content=\"" + map.TableName + "\", ";
queryFullText += string.Join (",\n", fullTextColsNames.ToArray ());
queryFullText += ", tokenize=" + map.FullTextTableTokenizer;
queryFullText += ")";

Execute (queryFullText);

// Create triggers to keep full text index in sync with content table
var deleteOldSql = "DELETE FROM \"" + map.FullTextTableName + "\" WHERE docid=old." + map.PK.Name + ";";
var insertNewSql = "INSERT INTO \"" + map.FullTextTableName + "\"(docid, " + string.Join (", ", fullTextColsNames);
insertNewSql += ") VALUES (new." + map.PK.Name + ", new." + string.Join (", new.", fullTextColsNames) + ");";

var beforeUpdateSql = "CREATE TRIGGER IF NOT EXISTS \"" + map.FullTextTableName + "_t_bu\" BEFORE UPDATE ON \"" + map.TableName + "\" BEGIN\n" + deleteOldSql + "\nEND;";
Execute (beforeUpdateSql);

var beforeDeleteSql = "CREATE TRIGGER IF NOT EXISTS \"" + map.FullTextTableName + "_t_bd\" BEFORE DELETE ON \"" + map.TableName + "\" BEGIN\n" + deleteOldSql + "\nEND;";
Execute (beforeDeleteSql);

var afterUpdateSql = "CREATE TRIGGER IF NOT EXISTS \"" + map.FullTextTableName + "_t_au\" AFTER UPDATE ON \"" + map.TableName + "\" BEGIN\n" + insertNewSql + "\nEND;";
Execute (afterUpdateSql);

var afterInsertSql = "CREATE TRIGGER IF NOT EXISTS \"" + map.FullTextTableName + "_t_ai\" AFTER INSERT ON \"" + map.TableName + "\" BEGIN\n" + insertNewSql + "\nEND;";
Execute (afterInsertSql);
}

return result;
}

Expand Down Expand Up @@ -2917,6 +2973,45 @@ public class StoreAsTextAttribute : Attribute
{
}

public enum FullTextSearchModule
{
FullTextSearch3 = 0,
FullTextSearch4 = 1
}

/// <summary>
/// Attribute to specify a full-text search table created from a subset of the
/// table columns. Name is the name of the FTS table, and Tokenizer is the tokenizer
/// to use, which can be one of the built-in tokenizers: "simple", "porter", "unicode61", or (possibly) "icu".
/// </summary>
[AttributeUsage (AttributeTargets.Class)]
public class FullTextTableAttribute : Attribute
{
public string Name { get; set; }
public string Tokenizer { get; set; }
public FullTextSearchModule Module { get; set; } = FullTextSearchModule.FullTextSearch4;

public FullTextTableAttribute ()
{
}

public FullTextTableAttribute (string name)
{
Name = name;
}

public FullTextTableAttribute (string name, string tokenizer)
{
Name = name;
Tokenizer = tokenizer;
}
}

[AttributeUsage (AttributeTargets.Property)]
public class FullTextIndexedAttribute : Attribute
{
}

public class TableMapping
{
#if NET8_0_OR_GREATER
Expand All @@ -2934,13 +3029,18 @@ public class TableMapping

public string GetByPrimaryKeySql { get; private set; }

public string FullTextTableName { get; private set; }

public string FullTextTableTokenizer { get; private set; }

public CreateFlags CreateFlags { get; private set; }

internal MapMethod Method { get; private set; } = MapMethod.ByName;

readonly Column _autoPk;
readonly Column[] _insertColumns;
readonly Column[] _insertOrReplaceColumns;
Column[] _fullTextColumns;

public TableMapping (
#if NET8_0_OR_GREATER
Expand Down Expand Up @@ -2969,6 +3069,23 @@ public TableMapping (
TableName = (tableAttr != null && !string.IsNullOrEmpty (tableAttr.Name)) ? tableAttr.Name : MappedType.Name;
WithoutRowId = tableAttr != null ? tableAttr.WithoutRowId : false;

#if ENABLE_IL2CPP
var fullTextTableAttr = typeInfo.GetCustomAttribute<FullTextTableAttribute> ();
#elif NET8_0_OR_GREATER
var fullTextTableAttr = type.GetCustomAttributes<FullTextTableAttribute> ().FirstOrDefault ();
#else
var fullTextTableAttr =
typeInfo.CustomAttributes
.Where (x => x.AttributeType == typeof (FullTextTableAttribute))
.Select (x => (FullTextTableAttribute)Orm.InflateAttribute (x))
.FirstOrDefault ();
#endif

if (fullTextTableAttr != null) {
FullTextTableName = fullTextTableAttr.Name != null ? fullTextTableAttr.Name : MappedType.Name + "_FT";
FullTextTableTokenizer = fullTextTableAttr.Tokenizer != null ? fullTextTableAttr.Tokenizer : "unicode61"; // The default "simple" tokenizer only supports ASCII so default to "unicode61" instead
}

var members = GetPublicMembers(type);
var cols = new List<Column>(members.Count);
foreach(var m in members)
Expand Down Expand Up @@ -3075,6 +3192,15 @@ public Column[] InsertOrReplaceColumns {
}
}

public Column[] FullTextColumns {
get {
if (_fullTextColumns == null) {
_fullTextColumns = Columns.Where (c => c.IsInFullTextIndex).ToArray ();
}
return _fullTextColumns;
}
}

public Column FindColumnWithPropertyName (string propertyName)
{
var exact = Columns.FirstOrDefault (c => c.PropertyName == propertyName);
Expand Down Expand Up @@ -3111,6 +3237,8 @@ public class Column

public IEnumerable<IndexedAttribute> Indices { get; set; }

public bool IsInFullTextIndex { get; private set; }

public bool IsNullable { get; private set; }

public int? MaxStringLength { get; private set; }
Expand Down Expand Up @@ -3151,6 +3279,7 @@ public Column (MemberInfo member, CreateFlags createFlags = CreateFlags.None)
) {
Indices = new IndexedAttribute[] { new IndexedAttribute () };
}
IsInFullTextIndex = Orm.IsInFullTextIndex (member);
IsNullable = !(IsPK || Orm.IsMarkedNotNull (member));
MaxStringLength = Orm.MaxStringLength (member);

Expand Down Expand Up @@ -3454,6 +3583,11 @@ public static bool IsMarkedNotNull (MemberInfo p)
{
return p.CustomAttributes.Any (x => x.AttributeType == typeof (NotNullAttribute));
}

public static bool IsInFullTextIndex (MemberInfo p)
{
return p.CustomAttributes.Any (x => x.AttributeType == typeof (FullTextIndexedAttribute));
}
}

public partial class SQLiteCommand
Expand Down
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