Stores alphabetic data, in which you specify the maximum number of characters for the field, i.e., CHAR (20) for a 20 character field. SQLite supports 8-byte integer columns and the FieldType evaluates to 19 (64-bit integer). The maximum number of digits is implementation-specific. If you are using another data source, check the documentation of your data source.Ī numeric data type with no fractional part. The maximum number of digits is implementation-specific, but is usually less than or equal to INTEGER. Stores the byte representation of a character string.Ī numeric data type with no fractional part. This table identifies the Column Type based on the FieldType Integer:ĭenotes the absence of any value, i.e., a missing value. Length: An integer that describes the length of the field (for some text fields), the precision of numeric data (for some numeric fields) or the default value for a field (for SQLite columns). NotNull: A boolean that indicates if the column can be set to NULL. IsPrimary: A boolean that indicates if the column is part of the primary key. TableColumns returns a RowSet with these columns:ĬolumnName: A string that is the name of the column.įieldType: An integer that describes the type of the column (refer to the table below). If an error occurs, a DatabaseException will be raised. This example stores a picture in a BLOB (db is a preexisting database): You can use the Database constants: MainDatabase ("main") and TempDatabase ("temp") as necessary. The row must exist when calling CreateBlob, it does not create a new record for you The row parameter is the rowid value, and not the actual row number, for example if you only have one record in your database, with a rowid of 100 then you would pass in a row of 100 and not 1 for example.Ĭreating a new blob automatically zeros the entire blob You can use this Constructor instead of manually assigning the data file using the DatabaseFile property.ĬreateBlob(tableName As String, columnName As String, row As UInt64, length As Integer, databaseName As String = "") As SQLiteBLOBĬreates a new BLOB column for the specified table and column at the specified row (rowID). This example sets WriteAheadLogging to True for a SQLite database:Ĭonstructors are special methods called when you create an object with the New keyword and pass in the parameters above.Ĭreates a SQLiteDatabase using the provided database file. WAL does not work over a network filesystemįor more information about WAL, refer to the SQLite documentation. The processes using the database must be on the same host computer Two extra files are created (*.sqlite-wal and *.sqlite-shm) alongside the main database file Rolling back large transaction (over 100MB) can be slow WAL database cannot be opened in read-only mode With Journaling, a database change writes to a rollback file and to the original database file.Īlthough faster, WAL does have some limitations: With WAL, a database change writes once to the write-ahead log. WAL is faster than normal mode (called Journaled) because there is less disk writing. If you want to use WAL, you need to set this property to True after connecting to the database by calling Connect. If your desktop app needs a multi-user database, it should use a database server. There is a high risk of database corruption. The SQLite organization does not recommend using SQLite on a network drive, even with WAL enabled. This is especially useful when multiple users are writing to the database, as can be the case with web applications. Message ) End TryĮnables the SQLite Write-Ahead Logging (WAL) mode which can improve performance of database writes. Connect // Key was correct DB is connected MessageBox ( "Connected to database." ) Catch error As DatabaseException MessageBox ( "Connection error: " + error. Var dbFile As New FolderItem ( "MyDB.sqlite" ) Var db As New SQLiteDatabase db. Query As String, Optional Paramarray values() As Variant TableName As String, columnName As String, row As UInt64, readWrite As Boolean, databaseName As String = "" TableName As String, columnName As String, row As UInt64, length As Integer, databaseName As String = ""Ĭommand As String, Optional Paramarray values() As Variant
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