SQLite adds a new field

Add a new field SQL statement by alter

"ALTER TABLE ' dihkchatmessage ' ADD  ' phonenum ' varchar";

But if this field already exists, the running program will crash directly, how to solve it?

Before adding a field, we can judge the database to see if the field already exists, as follows:

/**
 * Method 1: Check if a table column exists
 * @param db
 * @param tableName table name
 * @param columnName column name
 * @return
 */
Private static boolean checkColumnExist1(SQLiteDatabase db, String tableName
        , String columnName) {
    Boolean result = false ;
    Cursor cursor = null ;
    Try{
        / / Query a line
        Cursor = db.rawQuery( "SELECT * FROM " + tableName + " LIMIT 0", null );
        Result = cursor != null && cursor.getColumnIndex(columnName) != -1 ;
    }catch (Exception e){
        LogUtil.logErrorMessage("checkColumnExists1..." + e.getMessage());
    }finally{
        If(null != cursor && !cursor.isClosed()){
            Cursor.close() ;
        }
    }

    Return result ;
}


/**
 * Method 2: Check if a column in the table exists
 * @param db
 * @param tableName table name
 * @param columnName column name
 * @return
 */
Private static boolean checkColumnExists2(SQLiteDatabase db, String tableName, String columnName) {
    Boolean result = false ;
    Cursor cursor = null ;

    Try{
        Cursor = db.rawQuery( "select * from sqlite_master where name = ? and sql like ?"
                , new String[]{tableName , "%" + columnName + "%"} );
        Result = null != cursor && cursor.moveToFirst() ;
    }catch (Exception e){
        LogUtil.logErrorMessage("checkColumnExists2..." + e.getMessage());
    }finally{
        If(null != cursor && !cursor.isClosed()){
            Cursor.close() ;
        }
    }

    Return result ;
} 

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SQLite adds a new field