Although ESP32 supports wear-levelling, this is to be kept in mind before venturing into write-intensive database projects. Usually the limitation is 10000 writes or 100000 writes (on the same sector). These are expected to be made available shortly.Īny Flash memory such as those available on SPIFFS or Micro SD cards have limitation on number of writes / erase per sector. As of now many features of Sqlite3 have been omitted, except for basic table and index operations.
SQLITE LIMITATIONS CODE
So it cannot be reliably used in a multi-threaded / multi-core code set, except for read-only operations. It takes around 700 ms to retrieve from a dataset containing 10 million rows, even using the index. No serious limitations, except its a bit slow on large datasets.
The Sqlite3 code is included with the library. No dependencies except for the Arduino SDK. Open the examples from Arduino IDE, select board, port, upload and enjoy!! If you do not have the ESP32 sdk for Arduino, please see for installing it. Under Arduino15 folder please navigate to packages/esp32/hardware/esp32//libraries For example, it is usually found in the following locations: Windows: C:\Users\(username)\AppData\Local\Arduino15 The location varies according to your OS. Please download this library, unzip it to the libraries folder of your ESP32 sdk location. If you are using a board such as shown in the picture above, this wiring is ready-made. While there is no wiring needed for SPIFFS, for attaching cards to SPI bus, please use the following connections: * SD Card | ESP32Īnd for SD card attached to High-speed 4-bit SD_MMC port, use: * SD Card | ESP32 Please see the comments section of the example. The sample databases given (under examples/sqlite3_sdmmc/data folder) need to be copied to the Micro SD card root folder before the SD examples can be used.
SQLITE LIMITATIONS FULL
Please see the examples for full illustration of usage for the different file systems. The default mount points are: '/sdcard' // for SD_MMCĪnd the filenames are to be prefixed with these paths in the sqlite3_open() function (such as sqlite3_open("/spiffs/my.db") ). Even multiple cards can be supported on the SPI bus by specifying the pin number and mount point using the begin() method. The ESP32 Arduino core SDK has an excellent VFS layer. SPI.begin() SD.begin() // for Cards attached to the SPI bus Before calling please invoke: SD_MMC.begin() // for Cards attached to the High speed 4-bit port Sqlite3 C API such as sqlite3_open can be directly invoked.
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