Better example is here try { myDB = this.openOrCreateDatabase(“DatabaseName”, MODE_PRIVATE, null); /* Create a Table in the Database. */ myDB.execSQL(“CREATE TABLE IF NOT EXISTS ” + TableName + ” (Field1 VARCHAR, Field2 INT(3));”); /* Insert data to a Table*/ myDB.execSQL(“INSERT INTO ” + TableName + ” (Field1, Field2)” + ” VALUES (‘Saranga’, 22);”); /*retrieve data … Read more
The Java ResultSet is a pointer (or cursor) to the results in the database. The ResultSet loads records in blocks from the database. So to answer your question, the data is only fetched when you request it but in blocks. If you need to control how many rows are fetched at once by the driver, … Read more
The most likely issue is this line: FOREIGN KEY (classLeader) REFERENCES student(studentID), The datatype of classLeader is VARCHAR(255). That has to match the datatype of the referenced column… student.studentID. And of course, the student table has to exist, and the studentID column has to exist, and the studentID column should be the PRIMARY KEY of … Read more
Yes, DB2 has the MERGE statement, which will do an UPSERT (update or insert). MERGE INTO target_table USING source_table ON match-condition {WHEN [NOT] MATCHED THEN [UPDATE SET …|DELETE|INSERT VALUES ….|SIGNAL …]} [ELSE IGNORE] See: http://publib.boulder.ibm.com/infocenter/db2luw/v9/index.jsp?topic=/com.ibm.db2.udb.admin.doc/doc/r0010873.htm https://www.ibm.com/support/knowledgecenter/en/SS6NHC/com.ibm.swg.im.dashdb.sql.ref.doc/doc/r0010873.html https://www.ibm.com/developerworks/community/blogs/SQLTips4DB2LUW/entry/merge?lang=en
I wanted to know if the {save} method in CrudRepository do an update if it finds already the entry in the database The Spring documentation about it is not precise : Saves a given entity. Use the returned instance for further operations as the save operation might have changed the entity instance completely. But as … Read more
If you haven’t DELETEd any records, doing: SELECT MAX(_ROWID_) FROM “table” LIMIT 1; will avoid the full-table scan. Note that _ROWID_ is a SQLite identifier.
OrientDB (old link) appears to support graph storage in much the same was as Neo4j
You create custom initializer, which inherits from DropCreateDatabaseIfModelChanges or DropCreateDatabaseAlways interface. Like: public class EntitiesContextInitializer : DropCreateDatabaseIfModelChanges<-YourDbContext-> And then you overwrite Seed method like: protected override void Seed(YourDbContext context) Whole example might look like: public class EntitiesContextInitializer : DropCreateDatabaseIfModelChanges<EntitiesContext> { protected override void Seed(EntitiesContext context) { List<Role> roles = new List<Role> { new Role {Id=1, … Read more
If it’s part of a Database query you should be able to use a Parameterized SQL Statement. As well as escaping your quotes, this will deal with all special characters and will protect you from SQL injection attacks.
The advantages of enums are: Performance is better. You can just display what you get out of the core table instead of either having a separate lookup table that translates a code to a value or having app logic that translates a code to a value. This can be especially useful in datawarehouse applications. Ad … Read more